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# Discovery of Sound in the Sea

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## Posts

- [Ultrasonic Antifouling - November 1, 2024](https://dosits.org/ultrasonic-antifouling/) - Biofouling, the growth of marine organisms on in-water surfaces, is a perpetual and significant concern for all vessels. Hull biofouling can slow vessel speed, requiring the vessel to consume more fuel, resulting in an increased emission of greenhouse gasses. In addition to increasing drag on a vessel, biofouling by marine organisms within pipes can lead
- [How “Fight or Flight” May Affect Marine Mammal Vocalizations - April 4, 2025](https://dosits.org/how-fight-or-flight-may-affect-marine-mammal-vocalizations/) - Orca (Orcinus orca) in Haines, Alaska, United States. Photo credit: Christopher Michel Scientists have proposed several hypotheses, including fight or flight (Ford & Reeves, 2008), for how killer whale (Orcinus orca) predation has influenced baleen whales and broader ecosystems. Southern right whales have a robust body shape, with girth sometimes exceeding 60% of total body
- [Searching for MH370 - September 1, 2016](https://dosits.org/hot-topic-mh370/) - Searching for Malaysia Airlines Flight 370 UPDATE 2017: On January 17, 2017 the tripartite Ministers of Australia, Malaysia and China announced that the underwater search for MH370 was suspended. UPDATE: Upon further review, the pingers that were found in April are not thought to be from flight MH370. The search for Flight MH370 will continue using
- [Mass Stranding - June 4, 2017](https://dosits.org/hot-topic-mass-stranding/) - Mass Strandings The term stranding refers to an aquatic animal observed in an inappropriate location, for example, an offshore species found inshore. Most often, stranded animals are found on a beach or in shallow water. Along the U.S. coast alone, about 1,000 cetaceans and 2,500 pinnipeds strand annually. When three or more animals strand together in time
- [Ocean-Based Renewable Energy - June 6, 2017](https://dosits.org/hot-topic-ocean-based-renewable-energy/) - Ocean-Based Renewable Energy The European Union (EU) has committed to producing 20% of its energy from renewable sources by 2020. This has led countries such as Sweden, Ireland, Germany, and Denmark to be pioneers in developing a variety of technologies to harness and deliver energy. Systems associated with winds, waves, and tides produce underwater noise, the effects
- [Hearing Sensitivity - June 15, 2017](https://dosits.org/hot-topic-hearing-sensitivity/) - False killer whales can lower their hearing sensitivity A recent paper by Paul Nachtigall and Alexander Supin describes how a false killer whale is able to lower its hearing sensitivity before a loud sound when given a warning beforehand. Because many marine animals depend on their hearing for feeding and communication, loud sounds in the environment can have an impact
- [Monitoring Wind Farm Construction - June 25, 2017](https://dosits.org/hot-topic-monitoring-wind-farm-construction/) - Monitoring the Construction of the First U.S. Offshore Wind Farm for Potential Noise Impacts on Marine Life Wind energy is increasingly being used as an alternative energy source. Winds tend to be stronger and more uniform at sea than on land. In addition, there are large, potentially productive areas available offshore. Underwater sound is generated during the
- [Tracking Great White Sharks - July 9, 2017](https://dosits.org/hot-topic-tracking-great-white-sharks/) - Acoustic Tracking Technologies Shed Light on the Feeding Behavior of Great White Sharks Acoustic fish tags are used to monitor and track fish movements. Small tags are surgically implanted, injected, fed (via baited fish), or externally attached to a fish. The tags transmit a high frequency signal, and acoustic receivers are strategically placed around the area
- [Deep Ocean Sounds - July 11, 2017](https://dosits.org/deep-ocean-sounds/) - Hot Topic Scientists Measure Ambient Noise Levels in One of the Deepest Parts of the Global Ocean The ocean is filled with sound. Sound levels in the ocean differ from location to location and change with time. Some sounds are present more or less everywhere in the ocean all of the time. Some sounds, however,
- [Passive Acoustic Monitoring Critical to Vaquita Conservation Efforts - October 26, 2017](https://dosits.org/hot-topic-passive-acoustic-monitoring-critical-to-vaquita-conservation-efforts/) - An international team of experts have partnered on a “bold” conservation plan (VaquitaCPR; https://www.vaquitacpr.org) to prevent the most endangered marine mammal in the world, the vaquita porpoise (Phocoena sinus), from going extinct. The vaquita is only found in the upper portion of Mexico’s Gulf of California. Its population was estimated at 567 individuals in 1997,
- [Listening to Monterey Bay - May 30, 2018](https://dosits.org/hot-topic-listening-to-monterey-bay/) - Hydrophone Provides Continuous, Live Stream of Deep Sea Sounds from Monterey Bay The Monterey Accelerated Research System (MARS) cabled observatory, the first cabled oceanographic observatory on the U.S. West Coast, provides electrical power and data connections for research instruments deployed at 900 m (3,000 ft) below the surface of Monterey Bay. On July 28, 2015,
- [Measuring Methane Bubble Plumes - October 1, 2018](https://dosits.org/hot-topic-measuring-methane-bubble-plumes/) - Using Underwater Acoustics to Detect and Measure Global Ocean Methane Flux Methane (CH4) is a simple hydrocarbon, and is the primary component of the natural gas that is burned for energy production. Methane is a potent greenhouse gas because although methane is at a much lower concentration in the atmosphere than CO2, per molecule it
- [Seismic Airguns - December 20, 2018](https://dosits.org/hot-topic-seismic-airguns/) - An airgun is a tool used to examine layers of the seafloor and study the Earth’s history. It can also be used to locate subsea oil and gas deposits. Airguns rapidly release compressed air, causing a bubble to be formed. The formation of the bubble produces a loud sound that travels through the water to the
- [Killer Whales and Vessel Noise - May 10, 2019](https://dosits.org/hot-topic-killer-whales-and-vessel-noise/) - Measuring and mitigating the potential impacts of vessel noise on endangered killer whales Southern resident killer whales (SRKW) are an endangered marine mammal population found off the Pacific coasts of the United States and Canada. The population is comprised of three pods, whose known range extends from southeastern Alaska to central California. During the summer
- [Decoding the hum of submarine volcanic eruptions - January 16, 2020](https://dosits.org/decoding-the-hum-of-submarine-volcano-eruptions/) - Earthquakes and other geologic events produce acoustic signals that can be measured and monitored on land and underwater. Seismic energy from submarine earthquakes is converted into acoustic energy at the seafloor-water boundary. A Tertiary wave (or T-wave) is an acoustic signal associated with earthquakes. T-waves propagate efficiently in the ocean compared to seismic waves through
- [Changes in Baleen Whale Vocalizations - April 3, 2020](https://dosits.org/changes-in-baleen-whale-vocalizations/) - Decadal Decreases in the Frequency (Pitch) of Baleen Whale Vocalizations Baleen whales (mysticetes) are large cetaceans found throughout the global ocean. They include species such as humpback, blue, fin, bowhead, and gray whales. Although they are not known to echolocate, baleen whales produce a variety of underwater sounds to communicate, navigate underwater, and/or otherwise understand
- [Underwater Acoustic Impacts of COVID-19 - June 3, 2020](https://dosits.org/underwater-acoustic-impacts-of-covid-19/) - Updated October 16, 2020 Introduction The novel coronavirus (COVID-19) has had a major impact on society around the globe. Shelter-in-place orders and non-essential travel bans have had significant effects at all levels, from local to national economies. There have been unexpected, wide-ranging, trickle-down effects from these changes, including shifts in local and regional underwater noise
- [Sound waves from earthquakes can reveal changes in ocean temperature - February 5, 2021](https://dosits.org/hot-topic-sound-waves-from-earthquakes-can-reveal-changes-in-ocean-temperature/) - Background One of the ocean’s response to global climate change is a rise in average water temperature. Where in the ocean the warming occurs and the rate at which it occurs are of great interest to climatologists. Measuring ocean temperature to monitor and understand changes due to climate change presents some challenges because: • The
- [Seafloor exploration with fin whale calls - October 4, 2021](https://dosits.org/seafloor-exploration-with-fin-whale-calls/) - At the bottom of the ocean, there are layers of sediments that contain information about the Earth’s history and below the sediment are layers of the ocean crust. Seismic surveys (or sub-bottom profiling systems) are used to identify and characterize these layers of sediment and rock. The technique used is similar to a simple echosounder.
- [Glacial Calving in the Arctic Produces Record Source Levels - March 15, 2022](https://dosits.org/glacial-calving-in-the-arctic-produces-record-source-levels/) - Iceberg calving is a natural process, occurring when a rift opens in the edge of a glacier, caused by wind or water erosion, melting ice, or other events, resulting in an iceberg breaking away and falling into the ocean. The rate at which icebergs calve from glaciers increases with increased air and water temperatures. Polar
- [Using Drones to Deploy Digital Acoustic Tags - June 24, 2022](https://dosits.org/using-drones-to-deploy-digital-acoustic-tags/) - On June 8, 2022, the Bureau of Ocean Energy Management (BOEM) and the National Oceanic and Atmospheric Administration’s (NOAA) Stellwagen Bank National Marine Sanctuary announced the successful use of an uncrewed aerial vehicle (UAV, or drone), to deploy digital acoustic tags on 14 sei whales in the Northeast Atlantic. This marked a major innovation in
- [Underwater Sound and Coral Reef Restoration - September 14, 2022](https://dosits.org/underwater-sound-and-coral-reef-restoration/) - Global climate change is impacting the world’s coral reef ecosystems. Rapid ocean warming, and associated coral bleaching events, as well as increasing potential for impacts from tropical cyclones are causing significant damage to coral reefs. To better understand and mitigate these impacts, much work is being conducted in coral reef research, management, and conservation. A
- [Distributed acoustic sensing (DAS): Shedding light on passive acoustics - September 20, 2023](https://dosits.org/distributed-acoustic-sensing-das-shedding-light-on-passive-acoustics/) - A network of fiber-optic telecommunication cables spans 1.2 million km of the seafloor, covering both deep ocean and coastal areas around the globe. The cables are used to transmit phone calls, internet signals, and other data. Using a method called Distributed Acoustic Sensing (DAS), researchers are now working to repurpose these globally available telecommunication cables

## Pages

- [Home](https://dosits.org/) - Loading... How does sound travel in shallow water? The way in which sound speed changes with depth is not the same everywhere in shallow water. Southern Right Whale Southern right whales have a circumpolar distribution in the Southern Hemisphere. Hearing in Amphibious Marine Mammals The ears of amphibious marine mammals need to function both in
- [Sound and Signal: How Fishes Hear and Communicate Through Sound](https://dosits.org/decision-makers/webinar-series/2025-webinar-series/webinar-archive-fish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Sound and Signal: How Fishes Hear and Communicate Through Sound – September, 10 2025 Download the webinar outline with DOSITS links Download Dr. Joseph A Sisnero’s presentation as a PDF Download a summary of the webinar’s question/answer session Professional Development Questionnaire Post-Webinar Feedback
- [DOSITS Webinars](https://dosits.org/decision-makers/webinar-series/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Underwater Acoustics Webinar Series DOSITS offers an annual webinar series addressing a variety of topics (listed below). Each session lasts an hour and features up to two presenters, followed by a Q&A with attendees. The DOSITS webinar series is open to all
- [Ecological risk assessment frameworks: A spectrum of approaches, assumptions, and applications](https://dosits.org/decision-makers/webinar-series/2025-webinar-series/ecological-risk-assessment-frameworks/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ecological risk assessment is an increasingly common method used in evaluating the potential impacts of natural and human-induced impacts on protected species and environments. Such evaluations have been applied across a wide range of natural environments and taxa but share the use
- [Webinar Archive: Marine Invertebrates and Sound](https://dosits.org/decision-makers/webinar-series/2025-webinar-series/webinar-archive-marine-invertebrates/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Marine invertebrates and sound Overview Marine invertebrates represent the largest proportion of marine biomass and are indicators of ocean health. Recent studies have revealed there are large number of invertebrates sensitive to sounds. Sensory organs which allow the organisms to maintain equilibrium in
- [Hearing Loss in Fishes](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-fishes/hearing-loss-in-fishes/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Intense sounds of short duration or less intense, longer duration sounds may produce a temporary or permanent hearing loss. A temporary decrease in hearing sensitivity involves reversible damage to the inner ear and is called a temporary threshold shift (TTS). A permanent threshold shift
- [2025 Webinar Series](https://dosits.org/decision-makers/webinar-series/2025-webinar-series/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Underwater Acoustics: 2025 DOSITS Webinar Series DOSITS offers an annual webinar series addressing a variety of topics (listed below). Each session lasts an hour and features up to two presenters, followed by a Q&A with attendees. The DOSITS webinar series is open to
- [DOSITS Disclaimer](https://dosits.org/dosits-disclaimer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Discovery of Sound in the Sea Copyright © 2002-2023, University of Rhode Island Graduate School of Oceanography. All Rights Reserved. Contents contained on this website are provided on an “as is” basis. The University of Rhode Island Graduate School of Oceanography does
- [2022 Webinar Series](https://dosits.org/decision-makers/webinar-series/2022-webinar/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Underwater Acoustics: 2022 DOSITS Webinar Series DOSITS offers an annual webinar series addressing a variety of topics (listed below). Each session lasts an hour and features up to two presenters, followed by a Q&A with attendees. The DOSITS webinar series is open
- [2023 Webinar Series](https://dosits.org/decision-makers/webinar-series/2023-webinar/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Completed 2023 Webinars Natural underwater sounds overview on a global scale April 25, 2023 Dr. Jen Miksis-Olds, University of New Hampshire, Institute for the Study of Earth, Oceans, and Space. Extreme natural sounds June 6, 2023 Dr. Jackie Caplan-Auerbach, Western Washington University.
- [2024 Webinar Series](https://dosits.org/decision-makers/webinar-series/2024-webinar-series/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Underwater Acoustics: 2024 DOSITS Webinar Series DOSITS offers an annual webinar series addressing a variety of topics (listed below). Each session lasts an hour and features up to two presenters, followed by a Q&A with attendees. The DOSITS webinar series is open to
- [Webinar Archive: Project WOW - Collaborative research on offshore wind to advance integrated risk frameworks](https://dosits.org/decision-makers/webinar-series/2025-webinar-series/webinar-archive-marine-mammals/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Renewable energy development is occurring around the world, with large-scale offshore wind farms just beginning to be installed along the coastline of the eastern United States. A team led by Duke University is conducting a comprehensive evaluation of the potential effects of
- [Uncrewed Aerial Vehicle (UAV)](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/uncrewed-aerial-vehicle/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Underwater sound made by a drone (Inspire 1 Pro) flying 2 meters above the water surface, recorded by a hydrophone 1 meter below the surface (recorded in Iceland, water depth > 35 meters) Underwater sound made by a drone (Mavic Pro Platinum)
- [About DOSITS](https://dosits.org/about-dosits/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 The Discovery of Sound in the Sea website will introduce you to the science and uses of Sound in the Sea. There are several major sections on the site such as The Science of Sound in the Sea, People and Sound in
- [Potential effects of sound on marine invertebrates](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-invertebrates/) - Marine invertebrates involve a wide diversity of taxa, such as crustaceans, annelids, cephalopods, and gastropods. Given this diversity, marine invertebrates live in a variety of habitats including in the water column; others live close to, on, or within the seafloor. These habitats are acoustically complex, with multiple routes for sound and vibrations to travel within
- [Multibeam Echosounder](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/multibeam-echosounder/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Introduction Multibeam echosounders (MBES) are a type of sonar used to map the seafloor. In addition to collecting bathymetric data, these systems can make measurements relating to the characteristics of the seafloor and water column. Multibeam echosounders are used across numerous industries
- [Audio Gallery](https://dosits.org/galleries/audio-gallery/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sections: MARINE MAMMALSBaleen Whales Toothed Whales Pinnipeds SireniansMarine InvertebratesFishesOther Natural SoundsAnthropogenic Sounds– Share your audio with DOSITS! DOSITS is committed to making data publicly accessible for everyone. By sharing your audio, you’re contributing to open information and giving back to the marine
- [Torpedo](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/torpedo/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Torpedo Sounds A computer generated image of a torpedo being launched from a submarine. Image courtesy of Retinal Reality. Description Torpedoes used by underwater submarines produce more than just an explosive sound upon detonation. After an initial firing, the sound of the
- [Mantis Shrimp](https://dosits.org/galleries/audio-gallery/marine-invertebrates/mantis-shrimp/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Mantis Shrimp Sounds (Hemisquilla californiensis) Description The California mantis shrimp (shown here) produces sounds by vibrating its carapace, the hard, protective shell that covers the back of the animal. Image credit: Roy Caldwell, University of California, Berkeley (http://ib.berkeley.edu/labs/caldwell/) Mantis shrimp, also known as
- [Webinar Archive: Impulsive Sound and Offshore Wind](https://dosits.org/decision-makers/webinar-series/2024-webinar-series/webinar-archive-impulsive-sound-and-offshore-wind/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Impulsive Sound and Offshore Wind – October 16, 2024 Download the webinar outline with DOSITS links Download a summary of the webinar’s question/answer session Download Dr. Sander von Benda-Beckmann presentation as a PDF Dr. Sander von Benda-Beckmann, Netherlands Organization for Applied Scientific
- [What's New](https://dosits.org/whats-new/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025NEW content on DOSITS: DOSITS Webinars > 2025 Webinars > Webinar Archive: Marine Invertebrates and Sound Resources > Educator Resources > DOSITS Online Educator Professional Certificate Program – Spring 2025 BOAT Workshop – Learn ocean acoustics from theory to data practice with interactive
- [Resources](https://dosits.org/resources/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 EducatorMediaStudentsMeetingsEducator Teacher Resources and Web Links New! DOSITS Online Educator Professional Development Certificate Program Classroom Activities A Cup Of Sound Thinking Inside the Box Spectrograms Stirring up Sound How to Build a Hydrophone Videos Science of Sound Video Marine Mammal Hearing Hearing
- [DOSITS Online Educator Professional Development Certificate Program](https://dosits.org/resources-dosits-online-educator-professional-development-certificate-program/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 To attain the PD certificate, educators are required to complete a series of online assignments and participate in three virtual check-in meetings to discuss the content and have DOSITS team members answer questions. The assignments involve reviewing content on the DOSITS site,
- [Webinar Archive: Saturn Project Results: Underwater Radiated Noise from Vessels](https://dosits.org/decision-makers/webinar-series/2024-webinar-series/urn_saturn/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Webinar Archive: Saturn Project Results: Underwater Radiated Noise from Vessels – April 24, 2024 Download the webinar outline with DOSITS links Download Dr. Ir. Christ A.F. de Jong presentation as a PDF Download Dr. Ir. Johan Bosschers presentation as a PDF Download a
- [Webinar Archive: Multibeam Echosounders (MBES)](https://dosits.org/decision-makers/webinar-series/2024-webinar-series/webinar-archive-multibeam-echosounders-mbes/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Multibeam Echosounders (MBES) – September 18, 2024 Download the webinar outline with DOSITS links Download Dr. Hilary Kates Varghese's presentation as a PDF Download Michael Smith's presentation as a PDF Download a summary of the webinar's question/answer session Hilary Kates Varghese, BOEM Dr.
- [🌊 Sound travels far in the ocean—so can your curiosity. 🔊 Learn ocean acoustics with interactive Jupyter notebooks!](https://dosits.org/learn-ocean-acoustics-from-theory-to-data-practice-with-interactive-jupyter-notebooks/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ever wondered how whales chat across vast ocean basins? Or how we can “see” underwater without light to track fish or map the seafloor? If you’ve ever been curious about these questions, the Bridge to Ocean Acoustics and Technology (BOAT) program is
- [Webinar Archive: Saturn Project Results: Marine Mammals and Vessel Noise](https://dosits.org/decision-makers/webinar-series/2023-webinar/marine-mammals-vessel/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025
- [Humpback Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/humpback-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Humpback Whale Sounds (Megaptera novaeangliae) Description Underwater photograph of humpback whales in Hawaii. ©Tsuneo Nakamura. Humpback whales are probably the best known of all the baleen whales. Humpback whales are rorquals and are found in all parts of the ocean. They spend spring, summer, and
- [Webinar Archive: UN Ocean Decade: International Partnerships and Opportunities](https://dosits.org/decision-makers/webinar-series/2024-webinar-series/webinar-archive-un-ocean-decade-international-partnerships-and-opportunities/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 UN Ocean Decade: International Partnerships and Opportunities – May 15, 2024 Download the webinar outline with DOSITS links Download Dr. Grace Smarsh presentation as a PDF Download a summary of the webinar’s question/answer session Grace Smarsh, PhD AAAS S&T Policy Fellow Office of
- [Marine mammals feeding](https://dosits.org/animals/use-of-sound/marine-mammals-feeding/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 How do marine mammals use or make sound when feeding? Marine mammals use sound in a variety of ways while feeding. One well-known example is echolocation, in which animals produce short pulses of sounds that are reflected back when they strike an
- [Tutorial: How can we moderate or eliminate the effects of human activities?](https://dosits.org/tutorials/effects-introduction/moderate-effects/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Highlights: Moderate effects A variety of approaches have been used to reduce the effects of anthropogenic sound: *Avoidance of marine mammal habitats. *Detection of animals and modification of the sound-producing activities. *Modification or removal of the sound source. *Ramp-up of the sound
- [Moderate or eliminate the effects of human activities](https://dosits.org/animals/effects-of-sound/moderate-or-eliminate-the-effects-of-human-activities/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 How can we moderate or eliminate the effects of human activities? Some human activities contribute noise to the world ocean. Activities that produce sound include transportation, construction, defense, geophysical exploration, and oceanographic research. Federal laws such as the Endangered Species Act (ESA),
- [Beaked Whales](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/beaked-whales/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Beaked Whales Sounds Description The goose-beaked whale, was first described by naturalist Georges Cuvier. The species can be found in most parts of the ocean and seas worldwide. The average adult is about 5.5 m (18 ft) long and weighs 2500 kg (2.7
- [Dugong (Dugong Dugon)](https://dosits.org/galleries/audio-gallery/marine-mammals/sirenians/dugong/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 recording courtesy of Dr. Kotaro Ichikawa, Field Science Education and Research Center, Kyoto University Dugongs (Dugong dugon) are members of the order Sirenia, which also includes manatees. However, they are quite different from manatees in a number of morphological, physiological, and behavioral
- [How is sound used to detect illegal fishing?](https://dosits.org/people-and-sound/fishing/how-is-sound-used-to-detect-illegal-fishing/)
- [Using acoustics to explore the unknown ocean](https://dosits.org/people-and-sound/examine-the-earth/using-acoustics-to-explore-the-unknown-ocean/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Aristotle (384–322 BC) was among the first to note that sound could be heard in water as well as in air. Nearly 2,000 years later, Leonardo da Vinci (1452-1519) made an observation that ships could be heard at great distances underwater (Bjørnø
- [Tutorial: Mammals - Strandings](https://dosits.org/decision-makers/tutorials/effects/mammals-strandings/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 The term stranding refers to an aquatic animal observed in an inappropriate location, for example, an offshore species found inshore. Most often, stranded animals are found on a beach or in shallow water. Observations as far back as Aristotle[1]Aristotle. (1910). The History
- [Strandings](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-mammals/strandings/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 The term stranding refers to an aquatic animal observed in an inappropriate location, for example, an offshore species found inshore. Most often, stranded animals are found on a beach or in shallow water. Observations as far back as Aristotle[1]Aristotle. (1910). The History
- [Marine Mammalogist](https://dosits.org/galleries/career-gallery/marine-mammalogist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description A marine mammalogist is a scientist who specializes in the study of marine mammals. There are over 100 species of marine mammals including pinnipeds (seals, sea lions, and walrus), cetaceans (whales, dolphins, and porpoises), sirenians (manatees and dugongs), and some carnivores, such as
- [Behavioral Changes in Mammals](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-mammals/behavioral-changes-in-mammals/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Anthropogenic (human-made) sounds may affect the behavior of marine mammals. The occurrence and significance of a behavioral change varies by individual, species, and circumstances. Some sounds may not cause any response, while others may result in minor to significant changes in a
- [Passive Acoustic Recording Tags](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/passive-acoustic-recording-tags/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 A scientist prepares to tag a pilot whale with a passive acoustic recording tag. Image courtesy of Ari Friedlander/NOAA. Passive acoustic recording tags allow scientists to essentially accompany a whale or other marine animal while it is underwater, hear what it hears,
- [Tutorial: Mammals - Behavior Changes](https://dosits.org/decision-makers/tutorials/effects/mammals-behavior/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Anthropogenic (man-made) sounds may affect the behavior of marine mammals. The occurrence and significance of a behavioral change varies by individual, species, and circumstances. Some sounds may not cause any response, while others may result in minor to significant changes in a
- [Sonar](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/sonar/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sonar (Sound Navigation And Ranging) is the name of a technology that is used to detect objects in water and within the seafloor. There are two basic types – passive and active. Passive sonars listen for underwater sounds. Active sonar systems emit
- [Tutorial: Sonar Source](https://dosits.org/decision-makers/tutorials/sound-source/sonar/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sonar (SOund Navigation And Ranging) is the name of a technology that is used to detect objects in water and within the seafloor. There are two basic types – passive and active. Passive sonars listen for underwater sounds. Active sonar systems emit
- [Marine Mammal Hearing Attenuation](https://dosits.org/animals/advanced-topics-animals/marine-mammal-hearing-attenuation/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Toothed whales, including sperm whales, bottlenose dolphins, and harbor porpoises, use echolocation to navigate and locate prey. These odontocetes produce high frequency clicks that are reflected back as echoes when the click sounds strike an object(s). Differences between the original click and
- [Potential effects of sound on marine mammals](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-mammals/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 What are the potential effects of sound on marine mammals? How does anthropogenic (human-generated) sound affect marine animals? The ocean is full of both natural and anthropogenic sources of sound (see What are common underwater sounds?). Much attention has recently been focused
- [Potential effects of sound on marine fishes](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-fishes/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 What are the potential effects of sound on marine fishes? There are >33,000 species of extant fishes (FishBase), many of which are marine fishes. Marine fishes face threats from many different human activities, including overfishing, habitat degradation and loss, bycatch, and and
- [Impacts of Impulsive Sound](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-mammals/impacts-of-impulsive-sound/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Marine mammals are continuously exposed to anthropogenic sound sources, but not all acoustic signals are received equally by the animals. Mammalian hearing is sensitive and susceptible to damage from intense impulsive sound events; impulsive sounds, such as the soundwave accompanying underwater explosions,
- [Criteria for Effects of Anthropogenic Sound on Fishes](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-fishes/criteria-fishes/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Some anthropogenic sounds may affect fishes. These effects may include small changes in behavior that have no long-term consequences, behavioral changes that cause fishes to temporarily or permanently leave feeding or breeding sites or change migration pathways, temporary hearing loss, physiological changes that
- [Hurricanes](https://dosits.org/galleries/audio-gallery/other-natural-sounds/hurricanes/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Hurricanes Description Tropical cyclones, hurricanes (or typhoons) are massive storms that form over tropical waters. These intense storms may have wind speeds over 74 mph (119 km/h) to 180+ mph (289+ km/h), varying in strength from Category 1 to 5 on the
- [Webinar Archive: Extreme Natural Sounds](https://dosits.org/decision-makers/webinar-series/2023-webinar/extreme-sounds/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Extreme Natural Sounds – June 6, 2023 Download Dr. Caplan-Auerbach’s presentation as a PDF Dr. Caplan-Auerbach, Western Washington University Dr. Caplan-Auerbach is the Associate Dean of the College of Engineering and Science at Western Washington University, as well as a professor in the
- [Webinar Archive: Natural Underwater Sounds Overview](https://dosits.org/decision-makers/webinar-series/2023-webinar/natural-sounds/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Natural Underwater Sound Overview – Soundscapes – April 25, 2023 Download a webinar outline with DOSITS links Download Dr. Jennifer Miksis-Olds presentation as a PDF Dr. Jennifer Miksis-Olds, University of New Hampshire Dr. Jennifer Miksis-Olds is the Director of the Center for Acoustics
- [Marine Vibroseis](https://dosits.org/galleries/technology-gallery/observing-the-sea-floor/marine-vibroseis/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Marine vibroseis (marine vibrators) is a technique for creating a geophysical survey sound source by displacing a volume of water with a vibrating plate or shell to create a pressure wave. This technique is an alternative method to the traditional seismic airgun
- [Mid-frequency Active Sonar Sound](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/mfa-recording/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Description Image of the USS Cowpens CG-63 in dry dock. The hull mounted mid-frequency sonar is in the bulbous projection at the bow. Photo by the U.S. Navy, public domain. Mid-frequency active (MFA) sonars are used by navies around the world primarily
- [Multibeam Echosounder](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/multibeam-echosounder/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Multibeam echosounder sounds Multibeam echosounders (MBES) are advanced active sonar systems that emit a number of narrow sound waves in a fan shape (swath), using an array of transducers. Multibeam echosounders were first developed by the U.S. Navy in the 1960s [1].
- [Classroom Activities](https://dosits.org/resources/resource-categories/classroom-activities/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 A Cup Of Sound (Level: Elementary) This activity demonstrates how different variables affect the pitch of the sound produced by a cup made from a variety of materials. It is an example of a “slip-stick” method of generating sounds. File: Cup of
- [How animals extract information about the ambient environment: Passive listening](https://dosits.org/animals/use-of-sound/how-animals-extract-information-about-the-ambient-environment-passive-listening/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 By listening to sounds, much can be learned about the environment. As sound travels underwater from a source to a receiver, the features of the sound change. These features can be used by receivers as cues for useful information such as location,
- [How do fish detect sound?](https://dosits.org/animals/sound-reception/how-do-fish-hear/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sound is an important source of information for animals living in the marine environment and all vertebrates, and many invertebrates, have evolved sensory mechanisms for detecting, localizing, and interpreting many of these sounds. The hearing system of vertebrates first arose in fishes,
- [Multibeam Echosounder](https://dosits.org/galleries/technology-gallery/observing-the-sea-floor/multibeam-echosounder/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 History and Usage Sonar (Sound Navigation And Ranging) is a technology used to detect objects in the water and at and within the seafloor. There are two basic types of sonar – passive and active. Passive sonars listen for underwater sounds. Active
- [Pile driving](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/pile-driving/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Constructing large, marine structures, such as bridges, wharfs, wind turbines, and offshore oil and gas structures requires supports, called piles, that are driven into the seafloor. These piles, most often made of steel, though they can be made of wood or reinforced
- [Seismic Airguns](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/seismic-airguns/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 This is a picture of the bubble from an airgun off the U.S. Coast Guard Cutter Healy. Image courtesy of Paul Henkart, Scripps Institution of Oceanography. Seismic airguns are used primarily to examine the layers of the seafloor to study Earth’s history or
- [Wind Turbine](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/wind-turbine/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Offshore wind turbines at Barrow Offshore Wind off Walney Island in the Irish Sea. Image credit: Andy Dingley Wind power is one of the fastest growing energy sectors and is the focus of development in many countries around the world, especially in
- [Single Beam Echosounders](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/echosounders/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Echosounders are a type of sonar commonly used for a variety of tasks, including navigation, measuring bottom depth, and detecting schools of fish and plankton. Single beam echosounders emit a pulse of sound in a narrow cone (2°-12°). Echosounders estimate bottom depth
- [Ocean Acoustic Tomography Transmission](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/ocean-acoustic-tomography-transmission/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ocean Acoustic Tomography Transmission Sounds Description An HLF-5 acoustic source (250 Hz) being deployed from the Ocean Construction Platform (OCP) Seacon near Bermuda during July, 1990, for a tomography experiment. The acoustic source is the round, drum-like object mounted in the middle
- [Outboard Motor](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/outboard-motor/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Outboard Motor Sounds Description Photo of a zodiac with outboard engine. Photo Copyright Tom Kieckhefer Outboard motors are found on small boats that are popular in coastal waters. The propeller of an outboard motor is what creates sound. On smaller boats, like a
- [Personal Water Craft (PWC)](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/personal-water-craft-pwc/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Personal Water Craft Sounds A personal water craft (PWC) is a type of recreational vehicle on which a rider sits or stands. Image credit: Holly Morin. Description A personal water craft (PWC) is a type of recreational vehicle on which
- [Pile Driving](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/pile-driving/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Pile Driving Sounds Description Pile driving is a commonly used in coastal and offshore construction. Pile driving produces high sound pressure levels in both the surrounding air and underwater environment. Image credit: Stéphane Charette; Wikimedia. Pile driving is commonly used in the
- [Ship](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/ship/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ship Sounds Photo Copyright Tom Kieckhefer Photo courtesy of Peter Scheifele. Description Ships create noise from their propellers, motors and gears. The noise created by the motor is continuous and caused by the mini-explosions that occur as fuel burns rapidly inside
- [Sonar](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/sonar/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sonar Sounds Photo courtesy of L-3 ELAC Nautik Description Sonar is used by ships and submarines to search the ocean. Sound is transmitted, and data is collected from the return echo of the sound. The first sound heard is of the
- [Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar Sound](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/surtass-lfa-sonar-sound/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 SURTASS LFA Sonar Sounds Photos courtesy of the US Navy File Photo Photos courtesy of the US Navy File Photo. Description Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) sonar system is an antisubmarine warfare device designed by the US Navy.
- [Tidal Turbine](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/tidal-turbine/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Tidal Turbines Description Tidal turbines can reach heights of 26 meters (85 feet) with rotor diameters of 16-18 m (52-59 ft). They can rest directly on the seafloor (like the turbine shown here) or float in the water column. Tidal turbines can
- [Underwater Breathing Apparatus](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/underwater-breathing-apparatus/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Underwater Breathing Apparatus Sounds “Traditional” scuba systems include a steel or aluminum alloy cylinder of compressed air attached to a two-stage “demand regulator”. These systems produce underwater noise associated with the bubbles that are produced when the diver exhales, as well as
- [Wind Turbine Sounds](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/wind-turbines/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Wind Turbines Description Offshore wind turbines at Barrow Offshore Wind off Walney Island in the Irish Sea. Image credit: Andy Dingley Wind energy (or wind power) refers to the process by which turbines convert the movement of wind into electricity. Wind turbines
- [Propagation Modeling](https://dosits.org/science/advanced-topics/propagation-modeling/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Ocean acoustic propagation models estimate how acoustic energy travels through the ocean after being generated by an underwater sound source. The output of these models can be used to help understand and extract information about ocean acoustic phenomena and to predict potential impacts
- [Nyquist Sampling](https://dosits.org/science/advanced-topics/nyquist-sampling/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Hydrophones allow people to listen to underwater sound. They convert sound in water (pressure changes) into electrical signals (How is sound measured?). These electrical signals can be recorded and analyzed with computer programs to determine the properties of the sound wave, including
- [Webinar Archive: Signal Processing 101 & Soundscapes](https://dosits.org/webinar-archive-signal-processing-101-soundscapes-nyquist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Signal Processing 101 & Soundscapes October 12, 2022 Download a webinar outline with DOSITS links Download Dr. Kathleen Wage’s Presentation as a PDF Download Dr. John Ryan’s Presentation as a PDF Download a PDF transcript of the webinar question/answer session (coming soon)
- [Sound Pressure Levels and Sound Exposure Levels](https://dosits.org/science/advanced-topics/sound-pressure-levels-and-sound-exposure-levels/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Regulators use sound pressure levels (SPLs) and sound exposure levels (SELs) to characterize potential effects of sound on marine animals. Sound pressure level (SPL) is a means of characterizing the amplitude of a sound. There are several ways sound pressure can be
- [Frequency Weighting of Signal Levels](https://dosits.org/science/advanced-topics/frequency-weighting-of-signal-levels/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Most animals, including humans, marine mammals, and fishes, have varying sensitivity to sounds of different frequencies. Because animals do not hear equally well at all frequencies, frequency weighting is a method to quantitatively account for these differing sensitivities, particularly when considering whether
- [What is source level?](https://dosits.org/science/advanced-topics/source-level/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025Source level is a metric describing the power radiated by a sound source along a particular direction. It is a key component of the sonar equation and is used in conjunction with the concept of transmission loss to calculate received levels. (For more
- [Introduction to Phase](https://dosits.org/science/advanced-topics/phase/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 What is Phase? An important characteristic of a sound wave is the phase. Phase specifies the location or timing of a point within a wave cycle of a repetitive waveform. Typically, it is the phase difference between sound waves that is relevant,
- [Ocean Noise Variability and Noise Budgets](https://dosits.org/science/advanced-topics/ocean-noise-variability-and-noise-budgets/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ocean Noise Variability Sound levels in the ocean are not constant, but differ from location to location and change with time. Different sources of sound contribute to the overall noise level, including shipping, breaking waves, marine life, and other anthropogenic and natural
- [Cylindrical vs. Spherical Spreading](https://dosits.org/science/advanced-topics/cylindrical-vs-spherical-spreading/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Cylindrical and spherical spreading are two simple approximations used to describe how sound level decreases as a sound wave propagates away from a source. Spherical Spreading Spherical spreading describes the decrease in level when a sound wave propagates away from a source
- [Propagation from a sound source array in the near field and far field](https://dosits.org/science/advanced-topics/near-far-field-propagation/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Example of wave fronts from surface waves created from raindrops. Image by Robert Simmon, NASA GSFC Sometimes it is useful to have multiple sound sources that operate together. This is called a source array. Before looking at how sound moves away from
- [How does sound move? Wave Propagation and Huygens' Principle](https://dosits.org/science/advanced-topics/how-does-sound-move-wave-propagation-and-huygens-principle/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 The behavior of sound waves as they travel through a medium or reflect from an object can be found using a remarkably simple geometrical procedure, Huygens' Principle. This principle describes how wave fronts move. Photo courtesy of Robert Simmon, NASA GSFC A
- [How does sound travel in shallow water?](https://dosits.org/science/advanced-topics/shallow-water-propagation/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Illustration of a side view of the continental shelf. Image public domain. In the field of ocean acoustics, “shallow water” commonly refers to coastal waters extending from the shoreline out to the edge of the continental shelf to a depth of about
- [Statistical Uncertainty](https://dosits.org/science/advanced-topics/statistical-uncertainty/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Scientists make measurements of the natural world — first to describe it and then to understand the fundamental laws that govern its operation. There is uncertainty, however, due to the limited accuracy and precision of the measurements and to the variability that
- [How does sound travel in very shallow waters?](https://dosits.org/science/advanced-topics/how-does-sound-travel-in-very-shallow-waters/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 An aerial view of the Little Monie Creek component of Chesapeake Bay Maryland National Estuarine Research Reserve. Image credit: NOAA Ocean Service Shallow waters have special acoustic propagation properties, which is discussed in the Advanced Topic on shallow water propagation. As compared
- [SONAR Equation](https://dosits.org/science/advanced-topics/sonar-equation/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 The “sonar equation” is a systematic way of estimating the expected signal-to-noise ratios for sonar (SOund Navigation And Ranging) systems. The signal-to-noise ratio determines whether or not a sonar will be able to detect a signal in the presence of background noise
- [Detection Threshold for Sonar](https://dosits.org/science/advanced-topics/detection-threshold-for-sonar/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sonar (SOund Naviation And Ranging) is a technology that uses acoustical waves to detect and locate objects in the ocean. Active sonar systems, such as fish finders, echosounders, side-scan sonars, and military sonars, transmit a pulse of sound and then listen for
- [Webinar Archive: Signal Processing 101 & Soundscapes](https://dosits.org/decision-makers/webinar-series/2022-webinar/webinar-signal-soundscapes/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Signal Processing 101 & Soundscapes October 12, 2022 Download a webinar outline with DOSITS links Download Dr. Kathleen Wage’s Presentation as a PDF Download Dr. John Ryan’s Presentation as a PDF Download a PDF transcript of the webinar question/answer session (coming soon) Dr. Kathleen Wage,
- [Mid-frequency Active Sonar](https://dosits.org/galleries/technology-gallery/locating-objects-using-sonar/mfa/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Mid-frequency active (MFA) sonars are used by navies around the world primarily to detect submarines. The U.S. Navy classifies MFA sonars as those that emit frequencies between 1 kHz and 10 kHz while some other countries classify MFA with different frequency ranges.
- [Explosive Sound Sources Technology](https://dosits.org/galleries/technology-gallery/basic-technology/explosive-sound-sources/)
- [Webinar Archive: Marine Mammal Response to Noise](https://dosits.org/decision-makers/webinar-series/2023-webinar/mammal-reaction/) - How Marine Mammals Respond to Underwater Ambient Noise - October 2023 Download Dr Fannie Shabangu's presentation as a PDF Transcript of Q&A section of webinar - coming soon Dr Fannie W. Shabangu, Department of Forestry, Fisheries and the Environment, Cape Town, South Africa Dr Fannie W. Shabangu is a fisheries biologist in the Fisheries Management
- [Scientific Method](https://dosits.org/decision-makers/scientific-method/) - The scientific method is a systematic set of principles and procedures for generating and representing knowledge as accurately as possible. Scientists use the scientific method as an orderly process to ask questions about phenomena and [glossary_exclude]test[/glossary_exclude] the answers. The diagram below illustrates the scientific method. Observations lead to a question. Possible answers to this question
- [How is sound used to find submarines?](https://dosits.org/people-and-sound/national-defense/how-is-sound-used-to-find-submarines/) - Submarines have a unique advantage over other types of military vessels because they are able to stay hidden below the sea surface. One way of detecting and locating submarines is by using passive acoustics or active acoustics. The objective of passive acoustics is to detect the sounds produced by a submarine, such as propeller, engine,
- [How is sound used to map the seafloor?](https://dosits.org/people-and-sound/examine-the-earth/map-the-sea-floor/) - High-resolution maps of the seafloor (bathymetric maps) are important for ship navigation, geological research, habitat and ecosystem studies, and military activities. From antiquity to World War I, the depth of the ocean was measured by using a weighted rope with markings on it. Once sonar became commercially available after World War I, sound was used
- [Acoustic Fish Tags](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/acoustic-fish-tags/) - Acoustic fish tags are used to monitor and track fish movements. Small tags are surgically implanted, injected, fed (via baited fish), or externally attached to a fish. The tags transmit a high frequency "ping" which can be heard as far as half a kilometer away. Acoustic receivers are strategically placed around the area of interest to listen for these
- [Tutorial: Strandings](https://dosits.org/tutorials/effects-introduction/tutorial-strandings/) - Highlights: Strandings Whales sometimes come ashore and are stranded. There have been incidents in which there was a relationship between the time and location of beaked whale strandings and the use of multiple, mid-frequency sonars in nearshore areas. Why these whales stranded is not understood . Additional research is needed to increase our knowledge of
- [RAFOS Floats](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/rafos-floats/) - RAFOS floats (SOFAR spelled backward) are floating instruments designed to move with the water and track the water's movements. The SOFAR float was designed as an active device that sent a low frequency acoustic signal to stationary hydrophones that would record the arrival times of the signal. From the arrival times, the floats could be located and
- [Dr. Rossby](https://dosits.org/galleries/scientist-gallery/rossby/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Watch the interview with Dr. Thomas Rossby Download the Rossby interview transcript (PDF) About Dr. Rossby Dr. Thomas Rossby. Dr. Tom Rossby is a professor of oceanography at the University of Rhode Island Graduate School of Oceanography. His research specializes in using
- [How is sound used to study marine mammal distribution?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-study-marine-mammal-distribution/) - Each species of whale and dolphin produces distinctive sounds including songs, moans, clicks, sighs, and buzzes (See the Discovery of Sound in the Sea Audio Gallery). For instance, male humpback whales produce a long, patterned song at middle frequencies whereas fin whales produce loud, short, low frequency "pulses." Humpback whale songs can be typically heard in their
- [How do marine invertebrates produce sounds?](https://dosits.org/animals/sound-production/how-do-marine-invertebrates-produce-sounds/) - Marine invertebrates produce sound using a diverse array of mechanisms. These include stridulation, muscle contractions, cavitation, and rapping. Stridulation One method of marine invertebrate sound production, commonly found in crustaceans, involves stridulation, which is the rubbing of two body parts together. Different species of marine crustaceans use different anatomical structures to stridulate, including claws, legs,
- [Low Frequency Sound Production and Reception in Mammals](https://dosits.org/animals/advanced-topics-animals/low-frequency-sound-production-and-reception-in-mammals/) - Low frequency sounds have longer wavelengths than high frequencies. Because wavelength is equal to the speed of sound divided by frequency, the wavelength for any given frequency is approximately 4.5 times longer in water than in air. Lower frequencies can propagate farther with less transmission loss than higher frequencies in both air and water. Consequently,
- [How is sound used to protect marine mammals?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-protect-marine-mammals/) - Human impacts on marine animals include entanglements in open-ocean and coastal fisheries, interactions with aquaculture facilities, and ship strikes. Acoustic devices are being employed as a tool to reduce risk and decrease these human impacts. Explore the pages below to read through case studies and learn more about how sound can be used to protect
- [How is sound used to reduce vessel strikes?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-protect-marine-mammals/how-is-sound-used-to-reduce-vessel-strikes/) - Entrance channels to commercial ports and other, busy coastal waters overlap with the habitat for many cetaceans, including the critically engendered North Atlantic right whale. The total population for this species is approximately 340 animals[ref]Pettis, H. M., Pace, R. M. III, & Hamilton, P. K. (2023). North Atlantic Right Whale Consortium 2022 Annual Report Card.
- [How is sound used to mitigate marine mammal/fisheries conflicts?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-protect-marine-mammals/how-is-sound-used-to-mitigate-marine-mammal-fisheries-conflicts/) - Pingers: Reducing the Risk of Entanglement in Gillnet Gear Entanglements in fisheries is a global problem that affects at least 40 species of cetaceans. World-wide, over 300,000 cetaceans are estimated to be incidentally caught in fishing gear each year. Some species, such as the Vaquita, are threatened with extinction due to entanglement-related deaths. Small coastal
- [Galleries](https://dosits.org/galleries/)
- [DOSITS Webinar Privacy Policy](https://dosits.org/decision-makers/webinar-series/dosits-webinar-privacy-policy/) - About this Policy This privacy policy explains how DOSITS collects, shares and uses Personal Information collected for the DOSITS Underwater Acoustics Webinar Series and how you can exercise your privacy rights. Information DOSITS Collects DOSITS uses Eventbright as our platform to collect and store registration information for the DOSITS Webinars and communicate though email with people who
- [Sitemap](https://dosits.org/sitemap/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 DOSITS Online Educator Professional Development Certificate Program Search 🌊 Sound travels far in the ocean—so can your curiosity. 🔊 Learn ocean acoustics with interactive Jupyter notebooks! Home About DOSITS Science of Sound Sound What is sound? How do you characterize sounds? Amplitude
- [Considerations for “Contained” Studies in Laboratory or Captive Settings](https://dosits.org/animals/effects-of-sound/determine-if-a-sound-affects-a-marine-animal/laboratory-captive/) - Acoustic research on fishes and invertebrates conducted in the animals’ natural environment provides behavioral and environmental authenticity, incorporating realistic sound exposure and propagation scenarios. However, this work can be physically challenging and costly to implement. In contrast, lab-based studies using tanks or other enclosures are often cost effective and less time consuming. Lab-based studies also
- [West Indian Manatee](https://dosits.org/galleries/audio-gallery/marine-mammals/sirenians/manatee/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 West Indian Manatee(Trichechus manatus) Description A Florida Manatee (Trichechus manatus latirostris) in Crystal River, FL. Algae often grows on the backs and tails of manatees, which makes their skin color appear green or brown. A manatee’s leathery-looking, thick skin continuously flakes off,
- [Amazonian Manatee](https://dosits.org/galleries/audio-gallery/marine-mammals/sirenians/amazonian-manatee/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Amazonian Manatee (Trichechus inungui) Description Global distribution map for the three extant species of manatees. The range of the West Indian manatee is shown in blue/red (Florida subspecies in blue, Antillean in red); Amazonian manatee in yellow; and West African manatee in
- [African Manatee](https://dosits.org/galleries/audio-gallery/marine-mammals/sirenians/african-manatee/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 African Manatee (Trichechus senegalensis) Description Global distribution map for the three extant species of manatees. The range of the West Indian manatee is shown in blue/red (Florida subspecies in blue, Antillean in red); Amazonian manatee in yellow; and West African manatee in
- [Sound Scattering Layers](https://dosits.org/science/movement/sound-scattering-layers/) - As sound energy propagates through the sea, sound spreading, absorption, reflection, refraction, and scattering can impact the direction of underwater sound propagation and/or cause signal attenuation. In particular, scattering occurs when an underwater sound strikes inhomogeneities, such as the uneven seafloor, sea surface, and objects in the water column. Some of the sound may reflect
- [Anthropogenic Sound Sources](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/) - What are the potential effects of anthropogenic sound sources on marine animals? The ocean is full of both natural and anthropogenic sources of sound (see What are common underwater sounds?). Much attention has been focused on anthropogenic sound sources in the ocean and potential effects on marine animals. These effects may include an alteration in
- [Scientific Uncertainty](https://dosits.org/decision-makers/scientific-uncertainty/) - In the scientific process, absolute certainty is often difficult to achieve. Uncertainty is a factor of the process {method link} and does not [glossary_exclude]mean[/glossary_exclude] that a result, hypothesis, or theory is wrong. Scientists have developed formal methods to address scientific uncertainty. Outside the scientific community, these methods and associated terminology can be confusing. This may
- [Signal Processing](https://dosits.org/science/advanced-topics/signal-processing/) - Signal processing refers to techniques used in many fields to analyze and display characteristics of various phenomena. In underwater acoustics, [glossary_exclude]signal [/glossary_exclude]processing is used to detect, localize, and classify a sound of interest, referred to as the signal, in the presence of noise. Examples of signal processing techniques used to analyze the characteristics of sounds are
- [DOSITS Resources for Decision Makers](https://dosits.org/decision-makers/resources/) - Videos Science of Sound Video Marine Mammal Hearing Hearing in Marine Fishes Determining Mitigation and Monitoring Through the Ecological Risk Assessment Process Anthropogenic Sound Sources Commercial Vessel Traffic Echosounders Pile driving Seismic Airguns Sonar Wind Turbine Articles Underwater Acoustics for Everyone Sonars and Strandings: Are Beaked Whales the Aquatic Acoustic Canary? Long distance listening: A
- [Pygmy Blue Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/pygmy-blue-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Pygmy Blue Whale (Balaenoptra musculus brevicauda) Description Pygmy blue whale off Western Australia. Photo copyright: Micheline Jenner, Centre for Whale Research. The pygmy blue whale is one of three recognized subspecies of the blue whale and is found in the waters of
- [Cusk Eel](https://dosits.org/galleries/audio-gallery/fishes/cusk-eel/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Cusk eel (Family Ophidiidae) Description Female cusk-eel captured on Cape Cod, MA. Photo Credit: Rodney Roundtree. Cusk eels (family Ophidiidae) are demersal fishes often found in temperate and tropical waters worldwide. They comprise one of the most widespread families of deep-sea fishes.
- [Specialized Sounds in Cetacean Communication](https://dosits.org/animals/advanced-topics-animals/specialized-sounds-in-cetacean-communication/) - In water, sound typically propagates farther than light. Thus, it is not surprising that acoustic communication, defined as transmission of information from a signaling animal to a receiving animal, plays a key role in the behavior and social interactions of marine animals, especially marine mammals. Marine mammals, like cetaceans that live in cohesive social groups,
- [Melon-headed whale](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/melon-headed-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Melon-headed Whale (Peponocephala electra) Description Melon-headed whales (Peponocephala electra)are found commonly in pelagic, tropical, and sub-tropical waters throughout the world. Population estimates for melon-headed whales range from approximately 5,000 individuals throughout the Hawaiian islands to over 40,000 across the eastern tropical Pacific.
- [Sounds Associated with Aggression](https://dosits.org/animals/use-of-sound/marine-mammal-communication/sounds-associated-with-aggression/) - Aggression is a common occurrence in the world of marine mammals. Aggressive displays, or agonistic behavior, are often seen among members of a group or between individuals of different species. Sound can be an important component of agonistic behavior, such as growls as part of a threat display. Animals can listen to these sounds to
- [How did the COVID-19 pandemic affect underwater sound?](https://dosits.org/science/sounds-in-the-sea/covid-19/) - The coronavirus (COVID-19) pandemic caused significant impacts around the globe. By April 2020, half of the world’s population was under some form of lockdown, with many individuals ordered to stay at home to some degree. Many unexpected, trickle-down effects occurred, including changes to terrestrial and underwater soundscapes. Shelter-in-place orders and non-essential travel bans caused unprecedented
- [Small Vessels](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/small-vessels/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 This recording is of a 50 HP outboard engine starting up and going into gear. You will hear a “ratchet” like sound that is associated with the gears starting to engage.Sound courtesy of Tom Kieckhefer. Released under Creative Commons License, non-commercial attribution.
- [How is sound used to navigate underwater?](https://dosits.org/people-and-sound/navigation/how-is-sound-used-to-navigate-underwater/) - Underwater sound can be used to help ships navigate their way through the water. Sound can also be used to navigate remotely operated vehicles (ROVs), manned submersibles, and oceanographic equipment. A basic underwater navigation system uses a hydrophone and an acoustic tracking beacon. The hydrophone is attached to a boat, below the water and works
- [How is sound used to measure water depth?](https://dosits.org/people-and-sound/navigation/how-is-sound-used-to-measure-water-depth/) - The depths of the ocean have been charted since the early days of sailing using a method called sounding. A sounding line (a rope that has a weight attached) is lowered over the side of the ship. When the weight hits the seafloor, the line goes slack, and is marked at the water's surface. The
- [Sub-bottom Profiler](https://dosits.org/galleries/technology-gallery/observing-the-sea-floor/sub-bottom-profiler/) - Sub-bottom profiling systems are used to identify and characterize layers of sediment or rock under the seafloor. The technique used is similar to a simple echosounder. A transducer emits a sound pulse vertically downwards towards the seafloor, and a receiver records the return of the pulse once it has been reflected off the seafloor. Parts of the
- [How is sound used to study the Earth's history?](https://dosits.org/people-and-sound/examine-the-earth/how-is-sound-used-to-study-the-earths-history/) - At the bottom of the ocean, there are layers of sediments that contain information about the Earth's history. Sound is used to map and characterize these sediment layers. Sound is used to select the precise locations for coring or drilling sediment samples to study the history of Earth's climate and ocean. Scientists also use sound
- [How is sound used to explore for oil and gas?](https://dosits.org/people-and-sound/examine-the-earth/how-is-sound-used-to-explore-for-oil-and-gas/) - Oil and gas are found in deposits below the seafloor. Millions of years ago, tiny plants and animals died and were buried by layers of sand and silt. Over time, as they are buried by more material, heat from the Earth's interior and pressure from overlying sediments turn the plant and animal remains into oil
- [Airgun Technology](https://dosits.org/galleries/technology-gallery/observing-the-sea-floor/airgun-technology/) - An airgun is used to examine the layers of the seafloor to study the Earth’s history or explore for oil and gas. An airgun is designed to rapidly release compressed air, which forms a bubble. It does this in three basic steps shown in the series of figures below. The figures show the cross-section of a simple airgun.
- [Airgun](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/airgun/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Airgun Sounds Description This image shows a cross section of a small airgun. Image courtesy of USGS. Seismic airguns are used to examine the layers of the seafloor to study the Earth’s history or explore for oil and gas. An airgun is designed to
- [How does sound propagate through sediment?](https://dosits.org/science/movement/how-does-sound-propagate-through-sediment/) - The medium through which a sound travels affects the behavior of the sound. Sound behaves differently in air than in water, and likewise sound behaves differently in ocean bottom sediments. Sound can move into sediments from the ocean or originate within them. Common sources of sound that can propagate through the sediments are from natural
- [Beluga Whale, White Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/beluga-whale-white-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Beluga Whale Sounds (Delphinapterus leucas) Description Beluga whale spy-hopping. Photo courtesy of Robyn Angliss, NOAA, National Marine Mammal Laboratory. Beluga whales are toothed cetaceans that are easily identified by a white, stocky body and a protruding forehead called a melon. These whales,
- [Harbor Porpoise](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/harbor-porpoise/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Harbor Porpoise Sounds (Phocoena phocoena) Description The harbor porpoise is one of the smallest cetaceans- adults are 1.4-1.9 m (4.5-6 ft) in length and can weigh up to 90 kg (198 lb). Image courtesy of Ari Friedlander/NOAA. The harbor porpoise is found
- [What sounds can people hear?](https://dosits.org/science/measurement/what-sounds-can-we-hear/) - People don’t hear all sounds. For example, the sound a dog whistle is inaudible to people, but dogs can hear that sound. Marine animals can often hear sounds that people can’t hear. The sounds people hear best are sounds like human conversations. Scientists theorize that these animals best hear the sounds that they use every day, with
- [Gray Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/gray-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Gray Whale Sounds (Eschrichtius robustus) Description Aerial view of a gray whale female and calf migrating north to Bering Sea feeding grounds. Image credit: NOAA Fisheries. Gray whales are found in coastal waters of the North Pacific, with the largest population in the
- [Gray Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/gray-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Gray Seal (Halichoerus grypus) Description Gray seals have a characteristically long head with a curved nose. Adult female gray seals are about 7.5 ft long when mature and weigh about 550 lbs; adult males can reach up to 10 ft in body
- [Sound Travel in the SOFAR Channel](https://dosits.org/science/movement/sofar-channel/sound-travel-in-the-sofar-channel/) - In the deep ocean at mid-latitudes, the slowest sound speed occurs at a depth of about 800 to 1000 meters. This is called the sound speed minimum. The sound speed minimum creates a sound channel in which sound waves can travel long distances. Sound is focused in the sound channel because the sound waves are
- [Webinar Archive: DOSITS 20th Anniversary](https://dosits.org/decision-makers/webinar-series/2022-webinar/dosits-20th/) - DOSITS 20th Anniversary Webinar Wednesday November 30, 2022 Speakers A brief history of DOSITS is given and presenters discuss the current state of underwater acoustics knowledge and future research directions on the characterization of the underwater acoustic environment and the acoustics of marine mammals, fishes, and invertebrates. Short History of DOSITSGail Scowcroft, Associate Director Inner Space Center, University of Rhode
- [Sea Urchin (Kina)](https://dosits.org/galleries/audio-gallery/marine-invertebrates/sea-urchin-kina/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sea Urchin Sounds (Evechinus chloroticus) Description Kina (Evechinus chloroticus) is a sea urchin found in the shallow waters of New Zealand. Feeding sounds associated with Kina sea urchins dominate the evening chorus in the 700-2000 Hz frequency range. Image copyright: Ryan Photographic,
- [Ross Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/ross-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ross Seal (Ommatophoca rossii) Ross seal high, mid and low siren vocalizations recorded using a sonobuoy during the International Whaling Commission’s Southern Ocean Whale and Ecosystem Research at 69.06° S, 10.23° E in the Weddell Sea at 71 km from the sea
- [Brown meagre](https://dosits.org/galleries/audio-gallery/fishes/brown-meagre/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Brown meagre (Sciaena umbra) The sound files were recorded in July 2020 along the Venice inlets connecting the Venice lagoon with the sea. The recordings were obtained using a pre-amplified calibrated Colmar GP1280 hydrophone (sensitivity of −170 dB re 1V/μPa and frequency
- [Webinar Archive: Introduction to Underwater Acoustics](https://dosits.org/decision-makers/webinar-series/2022-webinar/webinar-archive-intro/) - Introduction to Underwater Acoustics Wednesday April 20, 2022 Download a webinar outline with DOSITS links Download Dr. Warren's Presentation as a PDF Download a PDF transcript of the webinar question/answer session Dr. Joseph Warren, [glossary_exclude]School[/glossary_exclude] of Marine and Atmospheric Sciences at Stony Brook University Dr. Warren is an associate professor (with tenure) in the School of Marine
- [Modeling and Prediction of Ocean Ambient Sound](https://dosits.org/resources/resource-categories/meetings/decade/) - As part of the UN Decade of Ocean Science for Sustainable Development and a follow-on to the First International Ocean Decade Conference, the Ocean Decade Laboratories will be held in 2021 and 2022. Ocean Decade Laboratories connect diverse actors from around the globe and act as a platform for catalyzing partnerships and co-designing Decade Actions.
- [How is sound used to monitor and study seagrass beds?](https://dosits.org/people-and-sound/investigate-marine-animals/monitor-seagrass/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Seagrasses are important marine plants that create a valuable habitat for other marine creatures by forming vast meadows or beds. They resemble and are more closely related to flowering plants on land than seaweed. As many as 76 species of seagrass have
- [Marine Mammal Trainer](https://dosits.org/galleries/career-gallery/marine-mammal-trainer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description In the marine world, animal training has primarily been limited to marine mammals, though scientists have attempted to train other marine animals with limited success. including dolphins, seals, sea lions, walruses, and sea otters. Marine mammal trainers
- [Ocean Sound Policies](https://dosits.org/decision-makers/ocean-policies/) - Page updated September, 2022 Underwater sound may affect marine species or habitats in a number of ways. Marine species might experience behavioral change, acoustic masking, hearing loss, or other physiological effects from sound exposure; the reader is referred to the Effects of Sound Tutorial for an overview of the potential effects to marine life from
- [Population Consequences of Disturbance](https://dosits.org/animals/advanced-topics-animals/population-disturbance/) - Anthropogenic sounds might affect the behavior and physiology of individual animals. These effects may have short- or long-term changes that could affect individual survival or reproduction, resulting in population changes (e.g., feeding or breeding affecting growth rate or population structure). A conceptual framework, termed the Population Consequences of Acoustic Disturbance (PCAD) model[ref]National Research Council (U.S.),
- [Webinar Archive:  Sound During Offshore Wind Developments](https://dosits.org/decision-makers/webinar-series/2022-webinar/offshore-wind/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Consideration of Underwater Sound During Offshore Wind Developments Download a Webinar Outline with LinksDownload a PDF of the BOEM presentationDownload a transcript of the Questions and Answer portion of the webinar (coming soon)
- [How do you characterize sounds?](https://dosits.org/science/sound/characterize-sounds/) - Sounds are often described as loud or soft; high-pitched or low-pitched. These words are commonly used to describe, or characterize, how sounds are perceived. Scientists, on the other hand, describe sounds with characteristics that can be measured using instruments. Scientists measure amplitude, which can be related to the common words describing the perception of sound:
- [What are common underwater sounds?](https://dosits.org/science/sounds-in-the-sea/what-are-common-underwater-sounds/) - The ocean is filled with sound. Underwater sound is generated by a variety of natural sources, such as breaking [glossary_exclude]waves[/glossary_exclude], rain, and marine life. It is also generated by a variety of man-made sources, such as ships and military sonars. You can listen to examples of many undersea sounds in the Audio Gallery. Some sounds
- [Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar Technology](https://dosits.org/galleries/technology-gallery/locating-objects-using-sonar/surtass-lfa-sonar/) - The Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) sonar system is an antisubmarine warfare device designed by the US Navy. The system has both passive and active components. The passive part of the system is called SURTASS. It consists of a long array of hydrophones to listen for underwater sounds, particularly submarines. When the submarine
- [Acoustic Masking in Mammals](https://dosits.org/animals/advanced-topics-animals/masking-mammals/) - There are concerns about how anthropogenic sounds may affect hearing and communication in marine mammals. One potential effect is acoustic masking in which sounds (masking sounds, or maskers) interfere with an animal’s ability to perceive, detect, or discriminate a different sound[ref]Fletcher, H., & Munson, W. A. (1937). Relation between loudness and masking. The Journal of
- [Webinar Archive: Acoustic Propagation Modeling](https://dosits.org/decision-makers/webinar-series/2022-webinar/modeling/) - Acoustic Propagation Modeling May 12, 2022 Download a webinar outline with DOSITS links Download a PDF of Dr. Thode's presentation Download a PDF transcript of the webinar question/answer session Dr. Thode’s research interests include marine mammal acoustics, advanced acoustic signal processing, and geoacoustic imaging, inversion, and tomography. His recent research has covered the following topics:
- [Ocean Observatories](https://dosits.org/galleries/technology-gallery/basic-technology/ocean-observatories/) - Ocean observatories are networks of instruments and sensors for measuring conditions in the ocean and atmosphere and are located in several places across the globe. These observatories have long-term [glossary_exclude]power[/glossary_exclude] supplies and permanent communications links to shore-based stations using both undersea cables and satellite communication technology. Some of these observatories are connected to shore by
- [Hearing Loss in Mammals](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-mammals/hearing-loss-in-mammals/) - The basic mechanism of sound detection is the same in all mammals, whether they live on land or in the sea. Sound waves are transformed to neural impulses in the inner ear, which are interpreted by the brain as sounds (see How do marine mammals hear sounds? ). Exposure to loud sounds can interfere with
- [Amplitude and Intensity](https://dosits.org/science/sound/characterize-sounds/intensity/) - A sound wave’s amplitude relates to the change in pressure caused by the wave measured at a specific location. The sound is perceived as louder if the amplitude increases, and softer if the amplitude decreases. This is illustrated below. DOSITS short video on amplitude. The amplitude of a wave is related to the amount of
- [2021 Webinar series](https://dosits.org/decision-makers/webinar-series/2021-webinar-series/) - Underwater Acoustics: 2021 DOSITS Webinar Series The 2021 Webinar series event recordings are listed below. View the 2022 DOSITS Webinar Series. The DOSITS Team will facilitate a free, four-part webinar series on underwater sound. Each webinar is scheduled for approximately 60 minutes and will be comprised of a presentation by one or more experts, followed
- [Commercial diver](https://dosits.org/galleries/career-gallery/commercial-diver/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Commercial divers build, repair, and inspect structures that are underwater. Divers may weld underwater cracks in offshore oil and gas rigs, lay the foundation for a bridge piling, inspect pipes in water treatment plants, or rig and
- [Southern Right Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/southern-right-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Southern Right Whale (Eubalaena australis) Description Right whales (Eubalaena sp.) are baleen whales found in the temperate to subpolar latitudes throughout the global ocean. Southern right whales have a circumpolar distribution in the Southern Hemisphere, with major breeding populations along the coasts
- [How is sound used to study coral reefs?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-study-coral-reefs/) - Coral reefs are noisy environments due to an abundance of sounds, including those from wind, [glossary_exclude]waves[/glossary_exclude], and various marine animals (for more information see What are common underwater sounds?). Reef sounds vary on a daily basis, by moon phases, and by seasons. Human-generated sounds are increasingly becoming part of many underwater soundscapes, especially in coastal
- [How is acoustics used to monitor Arctic marine mammals?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-acoustics-used-to-monitor-arctic-marine-mammals/) - This animation tracks the relative amount of ice of different ages from 1990 through early November 2016. Seasonal ice is darkest blue. Ice that is 9 or more years old is white. Video produced by the Climate.gov team, based on NOAA and NASA data provided by Mark Tschudi, University of Colorado-Boulder. Data processing by Hunter
- [Commercial Vessel Traffic](https://dosits.org/animals/effects-of-sound/anthropogenic-sources/commercial-vessel-traffic/) - Many marine animals are often found in areas with high levels of commercial vessel traffic. Given this spatial overlap, increasing shipping activities worldwide, and the potential overlap between audible frequency ranges and ship noise for many marine species, long term exposure to underwater noise associated with commercial vessel traffic is a topic of increasing public
- [What are soundscapes?](https://dosits.org/science/sounds-in-the-sea/what-are-soundscapes/) - Locations can be described by visible features called landscapes. For example, Hawaii’s landscape includes volcanic islands, tropical forests, and coral reefs. Paris’s landscape includes the Eiffel Tower. Another way to describe locations is by their soundscape. Soundscapes are “acoustic landscapes” consisting of the perceptible sound sources arriving at the location of an animal or acoustic
- [What sounds can animals hear?](https://dosits.org/science/measurement/what-sounds-can-animals-hear/) - Most animals, including marine mammals and fishes, hear best at the frequencies they produce and have varying sensitivity to sounds of different frequencies. Many species differ in their ability to hear at any one frequency. Scientists and audiologists often display hearing abilities as a curve or audiogram, a graph of intensity vs. frequency. The figure
- [How is sound measured?](https://dosits.org/science/measurement/how-is-sound-measured/) - Just as microphones are used to listen to sound in air, devices called hydrophones are used to listen to sound underwater. Microphones convert sound in air into electrical signals. The electrical signals can then be amplified, recorded, played back over loudspeakers, and transmitted over telephone lines. The electrical signals can also be used to measure
- [Sound Channel Variability](https://dosits.org/science/movement/sofar-channel/sound-channel-variability/) - The way in which sound speed changes with depth is not the same everywhere in the ocean because the ocean temperature and salinity profiles that determine sound speed can differ greatly from one location in the ocean to another. In the deep, open ocean, between roughly 40°S and 40°N, temperature decreases with depth, and
- [Sound Speed Minimum](https://dosits.org/science/movement/sofar-channel/sound-speed-minimum/) - The speed at which sound travels in the ocean is affected by temperature, salinity, and pressure. Sound travels faster with increasing temperature, salinity, and pressure (See How fast does sound travel?). In the deep, open ocean at mid-latitudes, roughly half-way between the equator and the North or South poles, water temperature decreases with depth, salinity
- [History of the SOFAR Channel](https://dosits.org/science/movement/sofar-channel/history-of-the-sofar-channel/) - In the spring of 1944, ocean scientists, Maurice Ewing and J. Worzel, departed Woods Hole, Massachusetts, aboard the research vessel R/V Saluda to [glossary_exclude]test[/glossary_exclude] a theory that predicted that low-frequency sound should be able to travel long distances in the deep ocean. A deep receiving hydrophone was hung from R/V Saluda. A second ship dropped
- [How does sound travel long distances? The SOFAR Channel](https://dosits.org/science/movement/sofar-channel/) - A sound channel exists in the ocean that allows low-frequency sound to travel great distances. This channel is called the SOund Fixing And Ranging , or SOFAR, channel. The following sections include information on how the sound channel was discovered and used over the years, how the sound channel is formed, how sound travels
- [Tutorial: Sound Channel](https://dosits.org/tutorials/science/tutorial-sound-channel/) - It is important to understand that the way sound travels is very much dependent on the conditions of the ocean. The sound speed minimum at roughly 1000 meter depth in mid-latitudes creates a sound channel that lets sound travel long distances in the ocean. Sound is refracted just as light is. Refraction occurs not only when light
- [Tutorial: Scattering](https://dosits.org/tutorials/science/tutorial-scattering/) - Seawater has bubbles, suspended particles, organisms, and many other things that affect sound as it travels through seawater it. The use of a flashlight can be used as an example to illustrate what happens. Most of the time, the flashlight creates a circle of light on objects at which it is pointed. However, what happens
- [Tutorial: Refraction](https://dosits.org/tutorials/science/tutorial-refraction/) - What do you see when you place a pencil in a glass of water? The pencil appears to bend where it enters the water. The pencil is not really bent. The light we see has bent as it moves from water to air. This is called refraction. This occurs because light moves more slowly in
- [Refraction](https://dosits.org/science/movement/how-does-sound-move/refraction/) - What do you see when you place a pencil in a glass of water? The pencil appears to bend where it enters the water. The pencil is not really bent. The light we see has bent as it moves from water to air. This is called refraction. This occurs because light moves more slowly in
- [Tutorial: Reflection](https://dosits.org/tutorials/science/tutorial-reflection/) - We have probably all heard echoes - when our voices repeat in large rooms, canyons, or tunnels. But what are echoes? How are they created? Echoes are reflections. Sound bounces off a surface such as the canyon walls and returns so you hear it again. Just as a mirror reflects light, hard surfaces such as
- [Why does sound get weaker as it travels?](https://dosits.org/science/movement/why-does-sound-get-weaker-as-it-travels/) - As you've probably already noticed, the closer you (the receiver) are to the source of the sound, the louder the sound is. If you want sound to travel (propagate) a long distance, it needs to start out loud. If we go back to the image of sound as a rock thrown into a pond and
- [Tutorial: Sound Spreading](https://dosits.org/tutorials/science/tutorial-spreading/) - If we think of a wave spreading out from a rock that is thrown into a pond, the further from the source, the bigger the circle formed by the wave. As the circle gets bigger, its total length (circumference) also gets bigger. Spreading loss occurs because the total amount of energy in a wave remains
- [Sound Spreading](https://dosits.org/science/movement/why-does-sound-get-weaker-as-it-travels/sound-spreading/) - If we think of a wave spreading out from a rock that is thrown into a pond, the further from the source, the bigger the circle formed by the wave. As the circle gets bigger, its total length (circumference) also gets bigger. Spreading loss occurs because the total amount of energy in a wave remains
- [Tutorial: Speed of Sound](https://dosits.org/tutorials/science/tutorial-speed/) - We know that sound travels. How fast does it travel? Sound travels about 1500 meters per second in seawater. That's approximately 15 soccer fields end-to-end in one second. Sound travels much more slowly in air, at about 340 meters per second, only 3 soccer fields a second.  Unfortunately, the answer is really not quite
- [How fast does sound travel?](https://dosits.org/science/movement/how-fast-does-sound-travel/) - We know that sound travels. How fast does it travel? Sound travels about 1500 meters per second in seawater. That's approximately 15 soccer fields end-to-end in one second. Sound travels much more slowly in air, at about 340 meters per second, only 3 soccer fields a second.  Unfortunately, the answer is really not quite
- [Tutorial: Wavelength](https://dosits.org/tutorials/science/tutorial-wavelength/) - A wave has a repeating pattern. One complete repetition of the pattern is a cycle. The time to complete a cycle is the period. The distance that a sound wave travels in one period is called the wavelength. Wavelength is related to the speed at which sound travels and can be calculated by dividing the
- [Tutorial: Projector (Sound Source)](https://dosits.org/tutorials/technology/tutorial-projector-sound-source/) - Just as a loudspeaker is used to produce sound in air, an acoustic projector or sound source is used to generate sound underwater. Loudspeakers convert electrical signals into sound in air. Similarly, acoustic projectors convert electrical signals into sound in water. (See How are sounds made?). Underwater sound sources (may also be called transducers) can be built in a
- [Tutorial: Frequency or Pitch](https://dosits.org/tutorials/science/tutorial-frequency/) - High-pitched or low-pitched refer to the frequency of a sound wave. Because sound travels in a wave, the characteristics that scientists use to describe sound, such as frequency, can be related to a picture of a wave. A wave has a repeating pattern. One complete repetition is called a cycle. The time to complete a
- [Tutorial: What is Sound?](https://dosits.org/tutorials/science/tutorial-what-is-sound/) - Sound is created by a vibrating object. Sound travels as a wave through a medium, for example, a liquid (such as water), a solid (such as the seafloor), or a gas (such as air). Therefore, sound does not exist in the vacuum of space. A sound wave is an example of a compressional or longitudinal
- [Tutorial: Intensity or Loudness](https://dosits.org/tutorials/science/tutorial-intensity/) - A sound wave’s amplitude relates to changes in pressure. The sound is perceived as louder if the amplitude increases, and softer if the amplitude decreases. This is illustrated below. DOSITS short video on amplitude. The amplitude of a wave is related to the amount of energy it carries. A high amplitude wave carries a large
- [Detection Threshold in Animal Hearing](https://dosits.org/animals/advanced-topics-animals/detection-threshold/) - Detection thresholds are often considered the threshold of hearing and are measured in very quiet conditions, thereby providing the best estimate of hearing sensitivity. An audiogram is defined as the detection thresholds measured for pure tones within the animal’s hearing range. Human hearing is usually tested in a soundproof booth in order to minimize interference
- [Vector Sensors](https://dosits.org/galleries/technology-gallery/basic-technology/vector-sensors/) - A vector sensor is an underwater listening device used to detect sounds in water and convert acoustic energy into electrical energy. Vector sensors differ from hydrophones, which are also underwater listening devices, in that vector sensors measure both the particle motion and pressure changes associated with a sound wave, while hydrophones measure only the pressure changes. Vector sensors can determine the
- [Wavelength](https://dosits.org/science/sound/characterize-sounds/wavelength/) - A wave has a repeating pattern. One complete repetition of the pattern is a cycle. The time to complete a cycle is the period. The distance that a sound wave travels in one period is called the wavelength. Wavelength is related to the speed at which sound travels and can be calculated by dividing the
- [Frequency](https://dosits.org/science/sound/characterize-sounds/frequency/) - High-pitched or low-pitched refer to the frequency of a sound wave. Because sound travels in a wave, the characteristics that scientists use to describe sound, such as frequency, can be related to a picture of a wave. A wave has a repeating pattern. One complete repetition is called a cycle. The time to complete a
- [What is sound?](https://dosits.org/science/sound/what-is-sound/) - Sound is created by a vibrating object. Sound travels as a wave through a medium, for example, a liquid (such as water), a solid (such as the seafloor), or a gas (such as air). Therefore, sound does not exist in the vacuum of space. A sound wave is an example of a compressional or longitudinal
- [Science of Sound Tutorial: Introduction](https://dosits.org/tutorials/science/) - This tutorial will introduce you to the topics and content available on the DOSITS web site involving the science of sound in the sea. It is suitable for grades 9-12. Additional science content is available in the Science of Sound section including Advanced Topics topics. Sounds produced by marine animals, natural processes, and human activities fill the ocean. Because
- [How do marine invertebrates detect sounds?](https://dosits.org/animals/sound-reception/how-do-marine-invertebrates-detect-sounds/) - There is evidence to suggest that invertebrates can detect both water-borne and substrate-borne particle motion (vibration). Water-borne particle motion is detected as movement in the surrounding aquatic medium, whereas substrate-borne vibration is detected as particle motion below the seafloor. Semi-terrestrial crabs[ref]Popper, A. N., Salmon, M., & Horch, K. W. (2001). Acoustic detection and communication by
- [The Cold War: History of the SOund SUrveillance System (SOSUS)](https://dosits.org/people-and-sound/history-of-underwater-acoustics/the-cold-war-history-of-the-sound-surveillance-system-sosus/) - The end of World War II (WWII) saw the beginning of the Cold War between the Soviet Union and the United States and its allies. By early 1950, the U.S. Navy realized that Soviet submarines, which were based on the best of German WWII technology, posed a grave threat to America’s security. Several secret technical
- [What units are used to measure sound?](https://dosits.org/science/measurement/what-units-are-used-to-measure-sound/) - The sciences involve quantitatively measuring properties of the natural world. When a scientist is making measurements, they must first identify the specific properties they will measure, how those measurements will be made, and what units they will use. For example, if a scientist is measuring the property of water depth, it would not be enough
- [Units Page for Regulators](https://dosits.org/decision-makers/units-page-for-regulators/) - Fact Sheet on Units for Regulators There are fixed units such as meters and relative units such as decibels (dB). Relative units are related to specific conditions. For example, decibels in water have a different relative value than decibels in air. Scientists have agreed to use 1 microPascal (μPa) as the reference pressure for underwater sound. In
- [Snapping Shrimp](https://dosits.org/galleries/audio-gallery/marine-invertebrates/snapping-shrimp/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Snapping Shrimp Sounds (Alpheus heterochaelis) Description Courtesy of the Department of Applied Physics, University of Twente Snapping shrimp are crustaceans that are widely distributed throughout tropical and temperate seas. These shrimp, usually a muddy green color, grow to about 5 cm (2 inches) long.
- [Bar Jack](https://dosits.org/galleries/audio-gallery/fishes/bar-jack/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bar Jack Sounds (Caranx ruber) Description Bar jack. Courtesy of Robert A. Patzner, University of Salzburg, Austria. The bar jack ranges from New Jersey through the Caribbean and Gulf of Mexico but is uncommon in the northwestern Gulf of Mexico. Although inhabiting
- [How does sound propagate from air into water?](https://dosits.org/science/movement/how-does-sound-propagate-from-air-into-water/) - In the simplest situations, sound travels through a medium in straight lines. However, at some point, the medium may have changes in temperature, salinity, or pressure that cause the speed of sound to change. This change in sound speed will bend or refract the sound. Sound will bend towards the region with a slower sound
- [Glossary](https://dosits.org/glossary/)
- [Hooded Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/hooded-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Hooded Seal (Cystophora cristata) Description Two male hooded seals, one with its septum inflated (“red balloon”). The inflatable nasal cavity of the male hooded seal nearly doubles the size of its head. When deflated, it hangs down in front of the animal’s
- [Search](https://dosits.org/search/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Search DOSITS pages and posts Search for: Popular pagesHomeAudio GalleryWhat's NewSonobuoysBlue WhaleHow does sound in air differ from sound in water?Vector SensorsWorld War I: 1914-1918What is sound?Humpback Whale
- [Webinar Archive: Noise Abatement Systems](https://dosits.org/decision-makers/webinar-series/2021-webinar-series/webinar-abatement/) - Noise Abatement Systems for Impact Pile-Driving: Technical options for complying with noise limits Thursday, November 4, 2021 - Dr Michael Bellmann Download a webinar outline with DOSITS links Download a PDF of Dr. Bellmann's presentation Download a summary of questions asked during the webinar - coming soon Technical Report mentioned during webinar - link to
- [Fin Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/fin-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Fin Whale (Balaenoptera physalus) Description Fin whales have long, slender bodies; V-shaped heads; and a hooked dorsal fin located far on their backs, close to their tail. These whales feed on krill, small schooling fish, and squid by lunging into schools of
- [Gulf Corvina](https://dosits.org/galleries/audio-gallery/fishes/gulf-corvina/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Gulf Corvina (Cynoscion othonopterus) Description Gulf Corvina Species: Cynoscion othonopterus Family: Sciaenidae Other Names: Gulf Weakfish Maps showing the species range of Gulf Corvina in the Gulf of California (teal hatched area in the smaller map to the lower right), and the
- [What components of sound are used for hearing?](https://dosits.org/animals/advanced-topics-animals/components-of-sound/) - There are a wide variety of ear structures in terrestrial and aquatic vertebrates and invertebrates. Ears in marine invertebrates and fishes evolved prior to ears in land animals whereas ears of marine mammals evolved from those of land mammals that returned to water and therefore readapted to hearing in water. Scientists investigate how ears of
- [Sound Surveillance System (SOSUS)](https://dosits.org/galleries/technology-gallery/locating-objects-by-listening-to-their-sounds/sound-surveillance-system-sosus/) - In the mid-1950's, during the Cold War, the US Navy installed an underwater surveillance system to track submarines. The Sound Surveillance System (SOSUS) is a multibillion-dollar network of hydrophone arrays mounted on the seafloor throughout the Atlantic and Pacific oceans. The SOSUS system takes advantage of the sound channel that exists in the ocean, which allows low-frequency sound to travel great
- [Reverberation](https://dosits.org/science/movement/how-does-sound-move/reverberation/) - Sound movement through water can be complicated by spreading, absorption, reflection, refraction, and scattering. All may affect sound paths and/or intensity. Sound waves moving through water may encounter differences in densities and sounds speeds because of numerous objects, inhomogeneities, and rough boundaries (seafloor and sea surface). These scatter the sound energy in many directions. Reverberation
- [Nassau Grouper](https://dosits.org/galleries/audio-gallery/fishes/nassau-grouper/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Nassau Grouper (Ephinephelus striatus) Description Nassau grouper are reef fish that reach up to 48 inches in length when mature. During the non-spawning season, adult fish are light beige, with dark brown, vertical bars, a large, black blotch on top of the
- [Autonomous Surface Vehicles](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/autonomous-surface-vehicles/) - A wide variety of autonomous vehicles are available for studying the marine environment. These include unmanned aerial systems (UAS), autonomous underwater vehicles (AUVs), and autonomous surface vehicles (ASVs). For more details on AUVs, please visit the DOSITS content on Underwater Gliders. This section will focus on ASVs. ASVs operate without a crew onboard, remaining at
- [How does sound move?](https://dosits.org/science/movement/how-does-sound-move/) - When you shine a flashlight, the beam of light travels in a straight line in the direction you point the flashlight. In the simplest situations, sound also travels in straight lines. In the ocean, however, interactions between the sound and water make the transmission of sound much more complicated. These effects include reflection, bending (refraction),
- [How does sea ice affect how sound travels?](https://dosits.org/science/movement/sea-ice/) - Sound speed increases with increasing temperature, salinity, and pressure, though salinity has a relatively small effect on sound speed. In polar regions, the water column has a nearly uniform temperature compared to temperature variations in mid-latitudes. Consequently, the increase in pressure with depth tends to be the dominant oceanographic variable affecting sound speed in polar
- [Webinar Archive: Causes of Hearing Loss in Marine Mammals](https://dosits.org/decision-makers/webinar-series/2021-webinar-series/webinar-hearing-loss/) - Causes of Hearing Loss in Marine Mammals Tuesday, October 5, 2021 - Dr. Darlene Ketten Download a webinar outline with associated DOSITS links Darlene Ketten is a marine scientist and neurophysiologist specializing in biomechanics of hearing and hearing loss. She received a B.A., Washington University; M.S., Massachusetts Institute of Technology, and Ph.D., Johns Hopkins Medical
- [Webinar Archive: Passive Acoustic Monitoring Overview](https://dosits.org/decision-makers/webinar-series/2021-webinar-series/webinar-passive-acoustic/) - Passive Acoustic Monitoring Overview: Applications for Marine Mammals and Fishes Thursday, April 8, 2021 - Dr. Sofie Van Parijs Download a webinar outline with associated DOSITS links Download a PDF of Dr. Van Parijs presentation Download a summary of questions asked during the webinar Dr. Sofie Van Parijs has worked on passive acoustic research from the
- [Marine invertebrate communication](https://dosits.org/animals/use-of-sound/marine-invertebrate-communication/) - How do marine invertebrates communicate using sound? Acoustic communication in marine invertebrates has not been studied to the same extent as it has been for other marine animals. However, several marine invertebrates have been found to produce sounds for defensive and courtship purposes. The snapping shrimp produces sound in a most interesting and unique way.
- [Webinar Archive: Acoustic Tags](https://dosits.org/decision-makers/webinar-series/2021-webinar-series/tags/) - Acoustic Tag Technologies and Applications Friday May 7, 2021 Download a webinar outline with DOSITS links Download Dr Jeff Kneebone's Presentation as a PDF Download a summary of the webinar’s question/answer session Some Dr. Kneebone's animations can be found on the Anderson Cabot Center for Ocean Life blog pages about sharks Dr. Susan Parks, Associate
- [Why is sound important to marine animals?](https://dosits.org/animals/importance-of-sound/why-is-sound-important/) - Hearing is the universal alerting sense in all vertebrates. Sound is so important because animals are able to hear events all around them, no matter where their attention is focused. Many species of blind amphibians, reptiles, fishes and mammals are known, but no naturally profoundly deaf vertebrate species have been discovered. Although hearing is important
- [Real-time Passive Acoustic Sensors](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/real-time-passive-acoustic-sensors/) - Real-time passive acoustic sensors record and analyze calls in (near) real-time and transmit the data back to shore. Cornell University and the Woods Hole Oceanographic Institution (WHOI) have developed automatic-detection buoys in association with an environmental compliance mandate for the Northeast Gateway Deepwater Port for liquefied natural gas (LNG) in Massachusetts Bay. The planned route to the LNG
- [Archival Marine Acoustic Recording Units (ARUs)](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/archival-marine-acoustic-recording-units-arus/) - The use of passive acoustic monitoring (PAM) has increased with the availability of relatively inexpensive devices to record large amounts of acoustic data on marine animals. One type of passive acoustic sensor is the archival marine acoustic recording unit (ARU). Archival refers to data that are collected and stored by the unit for analysis after
- [World War II: 1941-1945](https://dosits.org/people-and-sound/history-of-underwater-acoustics/world-war-ii-1941-1945/) - Because underwater acoustics was so important during WWI, the beginning of WWII marked the start of extensive research in underwater acoustics. However, during WWII, progress in underwater acoustics, as in other areas like radar and weapons, was shrouded in secrecy. At the end of WWII, the U.S. National Defense Research Committee published a Summary Technical
- [Webinar Archive: Fundamentals of Underwater Sound](https://dosits.org/decision-makers/webinar-series/2020-webinar-series/fundamentals/) - Fundamentals of Underwater Sound - Tuesday, June 2, 2020 - Dr. Tracianne Neilsen Download a webinar outline with associated DOSITS links (and other suggested resources) Download a PDF of Dr. Neilsen's presentation Download a summary of the webinar’s question/answer session Dr. Neilsen is an Associate Professor in the Physics and Astronomy Department at Brigham Young University. Traci's research
- [How is sound used to transmit data underwater?](https://dosits.org/people-and-sound/communication/how-is-sounds-used-to-transmit-data-underwater/) - Computers use digital data to transmit and receive information including e-mail messages and Internet web pages. Is it possible to transmit this kind of data underwater? Can a submerged submarine send and receive e-mail? Submarines do not have telephone or cable connections, and radio signals do not propagate underwater, so a submarine relies on sound
- [Reflection](https://dosits.org/science/movement/how-does-sound-move/reflection/) - We have probably all heard echoes - when our voices repeat in large rooms, canyons, or tunnels. But what are echoes? How are they created? Echoes are reflections. Sound bounces off a surface such as the canyon walls and returns so you hear it again. Just as a mirror reflects light, hard surfaces such as
- [How do marine animals use sound?](https://dosits.org/animals/use-of-sound/how-do-marine-animals-use-sound/) - Many marine animals rely on sound for survival and depend on unique adaptations that enable them to communicate, protect themselves, locate food, navigate underwater, and/or understand their environment. They may both produce sounds and listen to the sounds around them. Sounds are particularly useful for communication because they can be used to convey a great deal
- [2020 Webinar Series](https://dosits.org/decision-makers/webinar-series/2020-webinar-series/) - Underwater Acoustics: 2020 DOSITS Webinar Series The DOSITS Team facilitated a free, four-part webinar series on underwater sound. Each webinar was scheduled for approximately 60 minutes and was comprised of one, focused presentation (topics listed below), followed by a period of facilitated discussion. The webinar series was open to all interested individuals. 2020 Archived Webinars
- [2019 Webinar Series Archive: Anthropogenic Sound Sources](https://dosits.org/decision-makers/webinar-series/webinars-2019/) - Underwater Acoustics: Webinar Series for the International Regulatory Community 2019 Anthropogenic Sound Sources [glossary_exclude] The DOSITS Team facilitated a free, four-part webinar series on topics related to Anthropogenic Sound Sources for the international decision-making community. Each webinar lasted approximately 60 minutes and was comprised of one or two focused presentation (topics listed below), followed by
- [2018 Webinar Series Archive](https://dosits.org/decision-makers/webinar-series/webinars-2018/) - Underwater Acoustics: Webinar Series for the International Regulatory Community 2018 The DOSITS Team facilitated a free, four-part webinar series on topics related to underwater sound for the international decision-making community. Webinar topics included foundational science on sound reception and potential effects in marine mammals and [glossary_exclude]fishes[/glossary_exclude]. Each webinar lasted 60 to 90 minutes and was comprised
- [Webinar Archive: 2015-2016 Series](https://dosits.org/decision-makers/webinar-series/webinar-archive-2015-16/) - Underwater Acoustics: Webinar Series for the International Regulatory Community DOSITS Acoustics Webinars 2015-2016 Webinar topics include basic science concepts related to underwater sound, marine animal sound production/reception, and the potential effects of sound on marine animals. Content is all derived from peer-reviewed research. Each webinar lasts approximately 60 minutes and is comprised of two, 15-20
- [DOSITS Webinar Testing and Troubleshooting Tips](https://dosits.org/decision-makers/webinar-series/webinar-troubleshooting/) - The DOSITS Webinars take place on Zoom, an online platform for meetings and webinars. From your local computer, you will be able to view and hear a speaker’s presentation. Participants will have their microphones muted throughout the webinar. Questions can be asked in the Q&A box during the webinar. A very brief tutorial, walking participants
- [How is sound used to measure global climate change?](https://dosits.org/people-and-sound/research-ocean-physics/how-is-sound-used-to-measure-global-climate-change/) - Introduction The average temperature of the ocean is rising as the global climate warms. Where the warming occurs and the rate at which it occurs are of great interest to climatologists. There are several difficulties in measuring the kinds of temperature changes that interest climatologists: Because the ocean is very large, it is difficult to
- [How is sound used to measure temperature in the ocean?](https://dosits.org/people-and-sound/research-ocean-physics/how-is-sound-used-to-measure-temperature-in-the-ocean/) - The speed of sound in water depends on the water properties of temperature, salinity and pressure (directly related to the depth). A typical speed of sound in water near the ocean surface is about 1520 meters per second. That is more than 4 times faster than the speed of sound in air. The speed of
- [Sonar Equation Example: Passive Sonar](https://dosits.org/science/advanced-topics/sonar-equation/sonar-equation-example-passive-sonar/) - Acoustic Thermometry of Ocean Climate (ATOC): Signal-to-Noise Ratio The Acoustic Thermometry of Ocean Climate (ATOC) project used long-range, low-frequency sound transmissions to measure large-scale ocean temperature variability. Acoustic sources on Pioneer Seamount off central California and north of Kauai, Hawaii, transmitted to receivers several thousand kilometers distant. Sound speed increases with increasing temperature, and the
- [Webinar Archive: An International Comparison](https://dosits.org/decision-makers/webinar-series/2020-webinar-series/international-comparison/) - Regulation of Underwater Noise: An International Comparison Thursday November 19, 2020 Klaus Lucke – JASCO Applied Sciences, Australia Download a webinar outline with associated DOSITS links Download a PDF of the Webinar including additional slides Download a summary of the webinar’s question/answer session Dr. Lucke is a senior scientist at JASCO in Australia. He manages
- [How is hearing measured?](https://dosits.org/science/measurement/how-is-hearing-measured/) - Hearing is an important sense for most animals. However, all animals do not hear all sounds. For example, people can't hear the sound a dog whistle makes, but dogs can hear that sound. Most marine mammals can hear sounds that people can't hear. What sounds we, or a marine animal, can hear depends on the
- [How is sound used to monitor and defend harbors?](https://dosits.org/people-and-sound/national-defense/how-is-sound-used-to-monitor-and-defend-harbors/) - Harbors are complex environments with vessels delivering cargo, piers and pylons at which ships dock, swimmers, divers, and pleasure craft. To maintain safe and secure harbors, surveillance is needed to detect, classify, and monitor all local activities. Harbor monitoring technologies include in-air systems, such as radar, and underwater surveillance systems to detect divers, swimmers, underwater
- [Webinar Archive: Passive Acoustics Data](https://dosits.org/decision-makers/webinar-series/2020-webinar-series/passive-acoustics-data/) - How are Passive Acoustics Data Used to Inform the Decision-Making Process? Thursday, October 22, 2020 Dr. Elizabeth Henderson – U.S. Naval Information Warfare Center (NIWC), Environmental Readiness Branch Download a webinar outline with associated DOSITS links (and other suggested resources) Download a PDF of Dr. Henderson's presentation Download a summary of the webinar’s question/answer session
- [Masking in Mammals](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-mammals/masking-in-mammals/) - Masking occurs when noise interferes with an animal's ability to to perceive (detect, interpret, and/or discriminate) a sound[ref][glossary_exclude]Fletcher, H., & Munson, W. A. (1937). Relation between loudness and masking. The Journal of the Acoustical Society of America, 9(1), 78–78. https://doi.org/10.1121/1.1902030[/glossary_exclude][/ref]. Just as it can be difficult to hear someone talking at a loud party, elevated
- [Tutorial: Commercial Vessel Traffic](https://dosits.org/decision-makers/tutorials/sound-source/commercial-vessel/) - Many marine animals are often found in areas with high levels of commercial vessel traffic. Given this spatial overlap, increasing shipping activities worldwide, and the potential overlap between audible frequency ranges and ship noise for many marine species, long term exposure to underwater noise associated with commercial vessel traffic is a topic of increasing public
- [Ship Quieting Technologies](https://dosits.org/animals/effects-of-sound/moderate-or-eliminate-the-effects-of-human-activities/ship-quieting-technologies/) - Ship propellers, motors, and gears create sound. The sounds produced depend on numerous factors including ship type, size, hull shape, propulsion system, ship speed, and transit conditions. Unless close to a vessel, most of the sounds that ships produce are low frequency (below 500 Hz) and contribute to ocean ambient noise. Studies have shown that
- [Webinar Archive: NMFS Regulatory Approach](https://dosits.org/decision-makers/webinar-series/2020-webinar-series/nmfs/) - Review of NMFS Regulatory Approach to Underwater Noise - Thursday, July 23, 2020 - Jolie Harrison Download a webinar outline with associated DOSITS links Download a PDF of Jolie Harrison's presentation Download a summary of the webinar's question/answer session Jolie is the Chief of the Permits and Conservation Division in the Office of Protected Resources in
- [Weddell Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/weddell-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Weddell Seal Sounds (Leptonychotes weddelli) Description Weddell seal with pup. Photo courtesy of Jeanette Thomas, Laboratory of Sensory Biology, Western Illinois University. Weddell seals are found only in the Antarctic region. These seals can dive for up to 73 minutes and reach
- [Walrus](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/walrus/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Walrus Sounds (Odobenus rosmarus) Description Walrus in Bering Sea, Alaska, Photo courtesy of Office of NOAA Corps Operations. Walruses are only found in the Northern Hemisphere. They inhabit both the Northern Atlantic and Pacific oceans, with the Pacific walrus being larger (3%
- [Ringed Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/ringed-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ringed Seal Sounds (Phoca hispida) Description Baltic ringed seal. Courtesy of Anna Roos, Swedish Museum of Natural History Ringed seals have a circumpolar distribution in the northern hemisphere and can be found associated with sea ice throughout the Arctic Ocean and in
- [Hawaiian Monk Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/hawaiian-monk-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Hawaiian Monk Seal Sounds (Monachus schauinslandi) Description Hawaiian monk seal with pup. Photo courtesy of Pat Greene, National Geographic Society’s Remote Imaging Department (www.nationalgeographic.com/crittercam). The Hawaiian monk seal’s common name is thought to come from the folds of skin around its face
- [California Sea Lion](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/california-sea-lion/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 California Sea Lion Sounds (Zalophus californianus) Description Group of California sea lions at the surface (called a raft) in Monterey Bay, CA. Copyright Tom Kieckhefer California sea lions are probably the most familiar pinniped because they are often seen in zoos and aquariums. In
- [Spinner Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/spinner-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Spinner Dolphin Sounds (Stenella longirostris) Description Spinner dolphin. Photo courtesy of Ann Zoidis. This dolphin gets its names because of its unique behavior of rapidly spinning in air. The spinner dolphin is the most common small dolphin in the warm waters of
- [Risso's Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/rissos-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Risso’s Dolphin Sounds (Grampus griseus) Description Three Risso’s dolphins in Monterey Bay, CA. Copyright Tom Kieckhefer The Risso’s dolphin is the fifth largest delphinid. Adults reach approximately 4 m (13 ft) in length. Risso’s dolphins are distributed world wide and are mostly seen in
- [Pilot Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/pilot-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Pilot Whale Sounds (Globicephala spp.) Description A group of pilot whales with backs and fins at the surface (top photo). Breaching pilot whales – one vertical and one horizontal (bottom photos). Photos courtesy of Susan Shane. Pilot whales are large dolphins with
- [Narwhal](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/narwhal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Narwhal Sounds (Monodon monoceros) Description Three narwhals swimming in the high Arctic, showing their spotted skin coloration and the spiraled tusk of the middle individual. Photo courtesy of Kristin Laidre, University of Washington. The most conspicuous feature of the narwhal is its
- [False Killer Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/false-killer-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 False Killer Whale Sounds (Pseudorca crassidens) Description Photo of false killer whale in the Gulf of Mexico, courtesy of NOAA Fisheries. False killer whales got their common name because their skulls are similar to killer whales , not because their physical appearances are similar.
- [Dall's Porpoise](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/dalls-porpoise/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Dall’s Porpoise Sounds (Phocoenoides dalli) Description Biological illustration of the Dall’s porpoise (top to bottom: male, calf, and female). Note their distinctive gray, black and white body color; thick, robust body shape; small head; and small, triangular dorsal fin. Also, the tailstock and
- [Bottlenose Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/bottlenose-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bottlenose Dolphin Sounds (Tursiops truncatus) Description Mother and juvenile bottlenose dolphins head to the seafloor. Photo courtesy of M. Herko, OAR/National Undersea Research Program (NURP). These dolphins have short beaks called rostrums. Their bodies are gray or charcoal in color with a lighter
- [Amazon River Dolphin, Boto](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/amazon-river-dolphin-boto/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Amazon River Dolphin Sounds (Inia geoffrensis) Description River dolphin. Photos courtesy of David Weller. The Amazon river dolphin is entirely riverine, inhabiting river channels, tributaries and lakes. It goes by many names and is most commonly referred to as “boto” or “boutu.”
- [Sei Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/sei-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 See Whale Sounds (Balaenoptera borealis) Description A sei whale at the surface. Note the animal’s long body- due to their body length, researchers usually only capture a picture of a sei whale’s back (with dorsal fin), or its head, rarely both together.
- [North Atlantic Right Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/north-atlantic-right-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 North Atlantic Right Whale Sounds (Eubalaena glacialis) Description Aerial photograph of North Atlantic right whale and calf. Photo courtesy of New England Aquarium Right whales are found in the temperate to subpolar latitudes (between 20° and 60° in both hemispheres) throughout the
- [Minke Whales](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/minke-whales/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Minke Whale Sounds (Balaenoptera spp.) Description Minke whale in Monterey Bay. Photo courtesy of Tom Jefferson Until the late 1990s, only one species of minke whale was believed to exist, the common minke whale. However, in recent years, researchers have determined that
- [Bowhead Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/bowhead/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bowhead Whale Sounds (Balaena mysticetus) Description Two bowhead whales swimming away from the camera. Photo courtesy of Jill Schoenherr Bowhead whales are easily distinguished by their enormous head, white chin, and lack of dorsal fin. They have the longest baleen of the baleen whales, growing to
- [Sperm Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/sperm-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sperm Whale Sounds (Physeter macrocephalus) Description Underwater photograph of sperm whale. Photo courtesy of Hal Whitehead laboratory, Dalhousie University. Sperm whales are found throughout the ocean. Females, calves, and juveniles spend more time at low latitudes while males travel and forage more
- [Marine/Maritime/Underwater Archaeologist](https://dosits.org/galleries/career-gallery/marinemaritimeunderwater-archaeologist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Archaeology is the study of human history and culture through the examination of remains of past human activities. Such studies help to explain not only where and when people lived on the earth, but also why and
- [Haddock](https://dosits.org/galleries/audio-gallery/fishes/haddock/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Haddock Sounds (Melanogrammus aeglefinus) Description Male haddock are vocal during the spawning season. This image shows the termination of courtship, with the male haddock mounting the larger female before the fish release eggs and sperm simultaneously into the water. Image credit: Anthony
- [Arctic Char](https://dosits.org/galleries/audio-gallery/fishes/arctic-char/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Arctic Char (Salvelinus alpinus) Arctic char are cold water members of the Salmonid family that produce underwater sounds associated with internal air movement, as well as gravel displacement during spawning. Image credit: Department of Fisheries and Oceans, Canada. Description Arctic char (Salvelinus
- [Sonar Technology](https://dosits.org/galleries/technology-gallery/locating-objects-using-sonar/sonar/) - Sonar (sound navigation and ranging) is a technology that uses acoustical waves to sense the location of objects in the ocean. The simplest sonar devices send out a sound pulse from a transducer, and then precisely measure the time it takes for the sound pulses to be reflected back to the transducer. The distance to an object can
- [DOSITS FAQ](https://dosits.org/dosits-faq/) - Frequently Asked Questions 1. What are common underwater sounds? 2. Why is sound important to marine animals? 3. How does sound in water differ from sound in air? 4. What sounds can marine mammals hear underwater? 5. How do animals use sound underwater? 6. How do people use sound underwater? 7. How does sound travel
- [How is sound used to locate fish?](https://dosits.org/people-and-sound/fishing/how-is-sound-used-to-locate-fish/) - Some sonar systems are especially designed to locate fish. These systems use the same basic principle as other sonar systems - they transmit sound pulses, measure the time it takes for echoes to return, and calculate the distance to the objects. (See: How do people and animals use sound in the sea). Fish finding sonar units
- [Facts and Myths](https://dosits.org/facts-and-myths/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Underwater sound is a complex topic, requiring a foundation in multiple sciences to fully comprehend. It becomes even more complicated when animals are exposed to anthropogenic sounds. Scientists are just beginning to explore the questions that need to be answered. The scientific
- [Marine Resource Manager](https://dosits.org/galleries/career-gallery/marine-resource-manager/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Coastal Management Specialists use science, economics, and policy to study the physical nature, dynamics, and potential change of marine ecosystems, the impact of humans on them, and the techniques necessary to manage the marine environment. Their efforts
- [How is sound used to measure plankton?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-measure-plankton/) - Plankton are relatively small organisms that drift or float passively in the water. Planktonic animals, called zooplankton, are an important food source for many other marine animals, including fish, seals, and whales. Zooplankton swarm in dense patches within the water column or at the sea surface. Many planktonic animals have body parts that reflect sound,
- [Sonobuoys](https://dosits.org/galleries/technology-gallery/locating-objects-by-listening-to-their-sounds/difar/) - Sonobuoys use a transducer and a radio transmitter to record and transmit underwater sounds. There are three types of sonobuoys: passive, active, and special purpose buoys. Passive sonobuoys use a hydrophone to listen for sound energy from a target. Active sonobuoys use a transducer to send an acoustic signal and then listen for the return echo off an object. Special
- [Bryde's Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/brydes-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bryde’s Whale (Balaenoptera edeni) Description Unlike other rorquals, which have a single ridge on their rostrum, Bryde’s whales have three prominent ridges in front of their blowhole (some refer to this distinct feature as a “splashguard”). Image credit: NOAA Fisheries. Bryde’s (pronounced
- [Marine mammal navigation](https://dosits.org/animals/use-of-sound/marine-mammal-navigation/) - How do marine mammals use sound to navigate? Sound plays an important role in marine mammal navigation. It may be critical when other senses are of limited use. Echolocation by odontocetes (toothed whales) has been extensively investigated. They produce a rapid series of clicks and the return echoes provide important information about objects in their
- [Why do sounds have certain properties?](https://dosits.org/science/sounds-in-the-sea/why-do-sounds-have-certain-properties/) - Underwater sounds generated by marine animals and people have characteristics that depend on the purposes for which they will be used. It is important to understand why specific sounds or signals are chosen for specific tasks. For example, why do the echolocation signals generated by dolphins and killer whales differ from the songs of humpback
- [Marine Educator](https://dosits.org/galleries/career-gallery/marine-educator/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Marine educators work in a variety of creative ways to teach people of all ages about marine science and ocean conservation. Work in this career is varied and may include classroom instruction, outdoor investigation, and/or aquarium/exhibit presentations.
- [Controlled Exposure Experiments](https://dosits.org/animals/effects-of-sound/measure-marine-mammals-reaction-to-sound/controlled-exposure-experiments/) - Controlled exposure experiments are a field method in which controlled doses of sound are transmitted to focal animals for the purposes of assessing their behavioral and/or physiological responses[ref]Gordon, J., Thompson, D., & Tyack, P. (2003). Proceedings of the workshop: The use of controlled exposure experiments to investigate the effects of noise on marine mammals: scientific,
- [Australian Humpback Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/australian-humpback-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Australian Humpback Dolphin (Sousa sahulensis) Description Australian humpback dolphin jumping out of the water. This species of humpback dolphin lacks the prominent hump found in other species of Sousa, and their dorsal fin is lower and more triangular. They have grey bodies
- [Acoustic Modem](https://dosits.org/galleries/technology-gallery/communications-technology/acoustic-modem/) - An acoustic modem is used to transmit data underwater, much as telephone modems are used to transmit data over phone lines. An acoustic modem converts digital data into special underwater sound signals. These signals are then received by a second acoustic modem and converted back into digital data. Acoustic modems can be used for underwater telemetry, ROV and
- [How do people and animals use sound in the sea?](https://dosits.org/science/sounds-in-the-sea/people-animals-use/) - People and marine animals use sound in the sea to accomplish many tasks. Light travels only a few hundred meters in the ocean before it is absorbed or scattered. Since light travels relatively short distances in the ocean, sound is often used by animals for such basic activities as finding food or a mate, navigating,
- [The First Studies of Underwater Acoustics: The 1800s](https://dosits.org/people-and-sound/history-of-underwater-acoustics/the-first-studies-of-underwater-acoustics-the-1800s/) - The first successful measurements of the speed of sound in water were not made until the early 1800s. Using a long tube to listen underwater, as suggested by da Vinci, scientists in 1826 recorded how fast the sound of a submerged bell traveled across Lake Geneva. Colladon and Sturm measured the water temperature in the
- [Sonar Equation Example: Active Sonar](https://dosits.org/science/advanced-topics/sonar-equation/sonar-equation-example-active-sonar/) - Submarine Search Sonar: Signal-to-Noise Ratio Although the characteristics of submarine search sonars vary substantially for different systems, typical sizes of the terms in the sonar equation can be obtained by working through an example for a hypothetical mid-frequency sonar operating at 8,000 Hz. The active sonar equation is: SNR (decibels) = SL -2TL +TS -
- [What is intensity?](https://dosits.org/science/advanced-topics/what-is-intensity/) - Sound waves are characterized by compression and expansion of the medium as sound energy moves through it. This represents the pressure component of sound. At the same time, there is also back and forth motion of the particles making up the medium (particle motion). Particle motion is described by displacement, velocity, and acceleration. The intensity of a sound wave is defined as the
- [Measurement Errors](https://dosits.org/science/advanced-topics/statistical-uncertainty/measurement-errors/) - In order to understand the effects of measurement errors, consider the example of determining the speed of sound in seawater at a particular temperature, salinity, and pressure. This requires precise measurements of the distance between a sound source and receiver, the time that it takes the sound to travel from the source to receiver, and
- [Natural Variability](https://dosits.org/science/advanced-topics/statistical-uncertainty/natural-variability/) - In addition to the statistical uncertainty associated with measurement errors, biological and other natural systems have an uncertainty associated with the range of natural variability. In such cases, there is no one “true” value, and scientists use statistical tools such as the mean and standard deviation to describe the natural variability that occurs and answer
- [Resources for Educators](https://dosits.org/resources/resource-categories/resources-for-educators/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 The Resources for Educators include Printed Resources, Books with Activities for Teachers, Books for Students, and Internet Resources. They are presented below organized by the sections of the DOSITS website: Science and Sound, Animals and Sound, People and Sound, Technology and Sound. Science and SoundAnimals and SoundPeople
- [Hydrophone/Receiver](https://dosits.org/galleries/technology-gallery/basic-technology/hydrophonereceiver/) - A hydrophone is an underwater listening device. Just as a microphone is used to detect sound in the air, a hydrophone detects sounds in the water and converts the acoustic energy into electrical energy. Hydrophones listen to sounds in the sea, but do not transmit any sound, making them passive listening devices. People were listening
- [Crabeater Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/crabeater-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Crabeater Seal Sounds (Lobodon carcinophaga) Description Crabeater seals resting on an ice floe in the Western Antarctic Peninsula. The rake-like scars seen on the body of the far seal are most likely from leopard seals, their main predator. Image credit: Dan Costa,
- [Webinar Archive: Sound Reception in Marine Mammals](https://dosits.org/decision-makers/webinar-series/webinars-2018/sound-reception-mammals2018/) - Sound Reception in Marine Mammals - Tuesday, April 24, 2018 - Dr. Darlene Ketten Download the Webinar Outline with associated DOSITS links Darlene Ketten is a marine scientist and neurophysiologist specializing in biomechanics of hearing and hearing loss. She received a B.A., Washington University (Biology; French); M.S., Massachusetts Institute of Technology. (Biological Oceanography), and
- [Webinar Archive: Potential Effects of Sound on Marine Mammals](https://dosits.org/decision-makers/webinar-series/webinars-2018/potential-effects-mammals2018/) - Potential Effects of Sound on Marine Mammals - Tuesday, May 1, 2018 - Dr. Brandon Southall Download the Webinar Outline with associated DOSITS links Dr. Brandon Southall is President and Senior Scientist for Southall Environmental Associates (SEA), Inc. based in Santa Cruz, CA, a Research Associate with the University of California, Santa Cruz (UCSC), and
- [Webinar Archive: Sound Production and Reception in Teleost Fishes](https://dosits.org/decision-makers/webinar-series/webinars-2018/sound-production-reception-fishes/) - Sound Production and Reception in Teleost [glossary_exclude]Fishes[/glossary_exclude] - Tuesday, November 13, 2018 - Dr. Craig Radford. Download the Webinar Outline with associated DOSITS links Craig Radfordais an Associate Professor in the Institute of Marine Science, University of Auckland. Craig is a sensory physiologist focusing on hearing and sound production in both fish and crustaceans. Watch the recording
- [Webinar Archive: Potential Effects of Sound on Marine Fishes](https://dosits.org/decision-makers/webinar-series/webinars-2018/potential-effects-sound-fishes/) - Potential Effects of Sound on Marine [glossary_exclude]Fishes[/glossary_exclude] -Tuesday, November 27, 2018 - Dr. Arthur Popper. Download the Webinar Outline with associated DOSITS links Arthur N. Popper is professor emeritus and research professor in the Department of Biology at the University of Maryland. Dr. Popper’s research has focused on hearing, with a particular interest in the structure
- [Webinar Archive: Seismic Sources](https://dosits.org/decision-makers/webinar-series/webinars-2019/seismic-sources/) - Marine Seismic Acoustic Sources - Wednesday May 1, 2019 - Dr. Robert Gisiner Download a Webinar Outline with associated DOSITS links. Download the presentation (~70-MB) Download a summary of questions asked during this webinar. Dr. Gisiner is the Vice President of Marine Environment & Biology at the International Association of Geophysical Contractors. At IAGC ,
- [Webinar Archive: Pile Driving and Wind Turbines](https://dosits.org/decision-makers/webinar-series/webinars-2019/pile-turbine/) - Anthropogenic Acoustic Sources: Pile Driving and Wind Turbines - Wednesday, May 22, 2019, 12:00 pm EDT Pile Driving (Dr. James Miller & Dr. Kathy Vigness-Raposa) Download a Webinar Outline with associated DOSITS links Download the presentation (10.9 MB)(Dr Vigness Raposa) Download the presentation (15.5MB) (Dr. James Miller) Wind Turbines (Dr. Jakob Tougaard) Download a Webinar Outline with
- [Webinar Archive: Commercial Vessel Traffic](https://dosits.org/decision-makers/webinar-series/webinars-2019/commercial-vessel/) - Commercial Vessel Traffic - Wednesday, September 18, 2019 - Michelle Sanders & Tabitha Takeda Download a webinar outline with associated DOSITS links Michelle Sanders, Director, Environmental Policy, Transport Canada Michelle Sanders is the Director of Clean Water Policy within the Environmental Policy group of Transport Canada. She is responsible for the analysis, development and implementation of
- [Webinar Archive: Sonar, Echosounders & Military Sonar](https://dosits.org/decision-makers/webinar-series/webinars-2019/echo-sonar/) - Sonar Basics, Echosounders and Military Sonar Thursday, October 10, 2019. Download a webinar outline with associated DOSITS links Presentations by Dr. Kelly Benoit-Bird, Monterey Bay Research Institute (MBARI) Dr. Frans-Peter Lam, TNO, Acoustics & Sonar research group, The Hague, NL Watch the recording of the DOSITS Webinar: Sonar Basics, Echosounders and Military Sonar
- [Ice Cracking](https://dosits.org/galleries/audio-gallery/other-natural-sounds/ice-cracking/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ice Cracking Sounds Description Photo courtesy of NOAA. This sound is of the cracking and popping that sea ice makes. Ice makes loud noises underwater when it cracks. Sea ice cracks as the wind, waves, icebergs, and other sea ice push against
- [Tutorial: Can Animals Sense These Sounds Part II](https://dosits.org/decision-makers/tutorials/determine-affects/animals-sense-sounds-2/) - Turtles, Fishes, and Invertebrates How do sea turtles hear? Sea turtles are found throughout the ocean, except in cold, polar waters. At present, we do not have any reliable underwater recordings of sounds produced by turtles, nor do we know how well most sea turtle species hear sound either in air or underwater. Our best
- [Tutorial: Pile Driving](https://dosits.org/decision-makers/tutorials/sound-source/pile-driving/) - Installing large structures in shallow marine environments requires the insertion into the seabed of support elements, called piles, made of wood, steel, or reinforced concrete. These piles, once installed, extend from above the water surface to as much as several hundred feet below the seabed. Installing the piles may require impact pile driving, which uses
- [Tutorial: Mammals - Masking](https://dosits.org/decision-makers/tutorials/effects/mammals-masking/) - Masking occurs when noise interferes with an animal's ability to to perceive (detect, interpret, and/or discriminate) a sound[ref]Fletcher, H., & Munson, W. A. (1937). Relation between loudness and masking. The Journal of the Acoustical Society of America, 9(1), 78–78. https://doi.org/10.1121/1.1902030[/ref]. Just as it can be difficult to hear someone talking at a loud party, elevated
- [Bearded Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/bearded-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bearded Seal Sounds (Erignathus barbatus) Description Bearded seal on ice in the Arctic. Photo courtesy of OSAP/IOS CANADA. Bearded seals are cold water seals that live in the circumpolar regions of the northern hemisphere. These seals are named for their long, numerous whiskers
- [Leopard Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/leopard-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Leopard Seal Sounds (Hydrurga leptonyx) Description Leopards seals occur near and within the Antarctic pack ice. They are highly vocal during the breeding season (November to January), producing vocalizations described as “trills” and “hoots”. Image credit: NOAA/SWFSC Leopard seals are solitary
- [Blue Whale](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/blue-whale/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sounds of Blue Whale (Balaenoptera musculus) Description Blue whales have a long, bluish gray, tapered body; a flat U-shaped head; and a very small dorsal fin positioned far back on the body. The whales produce underwater sounds that can occur as singular
- [How is sound used to identify ecological hotspots?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-identify-ecological-hotspots/) - There are many definitions of the term “ecological hotspot,” but the general concept is that marine ecological hotspots are regions of high biodiversity or locations of higher local abundance of species. However, the spatial and temporal variability within the marine environment makes traditional place-based conservation measures, such as marine protected areas, very difficult to implement.
- [How is sound used to find objects on the ocean bottom?](https://dosits.org/people-and-sound/navigation/how-is-sound-used-to-find-objects-on-the-ocean-bottom/) - Sonar is used to find objects on the bottom of the ocean. Side scan sonar is one method used to look at the detail of the ocean floor. Side scan sonar instruments are towed behind ships and often called towfish or tow vehicles (shown below). Pulsed signals are transmitted from each side of the tow
- [Acoustic Issues Related to Diadromous Fishes](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-fishes/acoustic-issues-related-to-diadromous-fishes/) - Of the more than 33,000 species of extant fishes (FishBase), less than 1% migrate between marine and freshwater systems at different times in their life [glossary_exclude]cycle[/glossary_exclude] (diadromous fishes). Many diadromous fish populations are at historic lows and are classified as threatened or endangered under the U.S. Endangered Species Act (ESA). Diadromous refers to fishes that
- [Acoustician](https://dosits.org/galleries/career-gallery/acoustician/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description An acoustician is someone who specializes in the study of sound. Many people mistakenly believe that acoustics is strictly musical or architectural in nature. On the contrary, acoustics is the interdisciplinary study of sound, and the field
- [How is sound used to measure, detect, and track oil?](https://dosits.org/people-and-sound/examine-the-earth/how-is-sound-used-to-measure-detect-and-track-oil/) - Oil spills happen along the coast, as well as in lakes and rivers. Their environmental impacts can be considerable. Light oils are highly toxic to marine life but evaporate quickly. Heavy oils are less toxic but persist in the environment longer, potentially mixing with pebbles and sandy beaches where they remain for years. Oil spill
- [Zoologist](https://dosits.org/galleries/career-gallery/zoologist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Zoology is a broad division of biology. Zoologists are biological scientists that study the study the characteristics, behavior, and habitats of animals. Many work to increase the knowledge and understanding of wildlife species. They may be involved
- [How are sounds viewed and analyzed?](https://dosits.org/science/measurement/how-are-sounds-viewed-and-analyzed/) - Most natural sounds have multiple frequencies and intensities that change over time. Scientists and musicians often use graphics to display the components present in a sound. Throughout this website, visualizations are used to help describe sound. In the Audio Gallery, for example, each sound may be displayed as an animated frequency spectrum, a waveform and
- [Tutorial: Wind Turbine](https://dosits.org/decision-makers/tutorials/sound-source/wind-turbine/) - Wind power is one of the fastest growing energy sectors and is the focus of development in many countries around the world, especially in Europe. In 2007, European leaders agreed to source 20% of their energy needs from renewable sources. Wind turbines convert wind energy into electricity. Winds tend to be stronger and more uniform over
- [CTBT Hydrophone Station](https://dosits.org/galleries/technology-gallery/locating-objects-by-listening-to-their-sounds/ctbt-hydrophone-station/) - The Comprehensive Nuclear-Test-Ban Treaty (CTBT) banned all nuclear explosions on Earth whether for military or for peaceful purposes. To verify compliance with the treaty, the CTBT includes an extensive International Monitoring System (IMS) to locate all types of nuclear tests (in air, on land, underground, and underwater). The IMS is a network of over 300
- [How does shipping affect ocean sound levels?](https://dosits.org/science/sounds-in-the-sea/how-does-shipping-affect-ocean-sound-levels/) - Commercial ships carrying a wide variety of cargos travel the world ocean. Ships’ propulsion systems and other machinery generate underwater noise. Cavitation that occurs at the propeller blade tips is a particularly significant source of noise. Cavitation takes place when the rotating blades cause the local pressure in water to drop below a critical value
- [How is sound used to estimate marine mammal abundance?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-estimate-marine-mammal-abundance/) - When scientists study a marine mammal population, they often ask, “How many individuals are there?” Estimating abundance (population size) and animal density (number of animals per unit area) are critical to properly understand marine mammal ecology as well as make important and effective management and conservation decisions. Traditionally, visual surveys have been used to estimate
- [Hearing Sensitivity Studies](https://dosits.org/animals/effects-of-sound/measure-marine-mammals-reaction-to-sound/hearing-sensitivity-studies/) - Knowledge of the hearing abilities and other acoustic features of marine animals is important when measuring the effects of sound on marine animals. (For more information see How do marine animals hear sounds?). Hearing studies provide information that may be used to predict how sound sources and levels may affect animals in the wild. If
- [Blast Injury, Barotrauma, and Acoustic Trauma](https://dosits.org/animals/advanced-topics-animals/blast-injury/) - Underwater explosions can create large sound pressures. With an explosion, there is an extremely rapid conversion of a solid or liquid into gases with high temperatures, pressures, and volumes. This conversion creates a “shock wave” that is characterized by an exceptionally high pressure that is almost instantaneous (rise time on the order of microseconds), followed
- [How did odontocete hearing evolve?](https://dosits.org/animals/advanced-topics-animals/how-did-odontocete-hearing-evolve/) - Cetaceans evolved from ancestors that had air-adapted ears. Their entire body, including their auditory systems, underwent significant adaptations related to living in water. These include the shape of the skull, the formation of a pathway for receiving sound energy in water, and some components of the inner ear. The following movie shows the anatomical adaptations
- [Hearing Loss Advanced Topic](https://dosits.org/animals/advanced-topics-animals/hearing-loss-advanced/) - Hearing loss is commonly categorized by why hearing no longer works, either as sensorineural or conductive. Sensorineural hearing loss means that hearing was lost by damaging the nerves or inner ear structures. Conductive hearing loss means transmission of sound to the inner ear is impaired. Either of these types of hearing loss can come from
- [Individual-specific Vocalizations](https://dosits.org/animals/use-of-sound/marine-mammal-communication/individual-specific-vocalizations/) - Many cetacean species have highly developed communication systems to establish or maintain contact with group members. Among the best studied of these vocalizations are the signature whistles of bottlenose dolphins. Each bottlenose dolphin has a unique signature whistle used to broadcast the animal’s identity and location. During the first year of life, a dolphin develops
- [Decision Makers](https://dosits.org/decision-makers/) - DOSITS Videos DOSITS Fact Sheet > Seismic Airguns
- [Science Tutorial: What is Sound?](https://dosits.org/decision-makers/tutorials/science/what-is-sound/) - Sound is created by a vibrating object. Sound travels as a wave through a medium, for example, a liquid (such as water), a solid (such as the seafloor), or a gas (such as air). Therefore, sound does not exist in the vacuum of space. A sound wave is an example of a compressional or longitudinal
- [Media Backgrounder](https://dosits.org/resources/resource-categories/media-backgrounder/) - Media Backgrounder- How do animals hear under water? The ocean is full of both natural and anthropogenic sources of sound. Much attention has recently been focused on anthropogenic sources of sound in the ocean and their potentially harmful effects on marine animals. This has become a topic of increasing controversy, especially regarding marine mammals. Only by understanding
- [Science Tutorial: Wavelength](https://dosits.org/decision-makers/tutorials/science/wavelength/) - A wave has a repeating pattern. One complete repetition of the pattern is a cycle. The time to complete a cycle is the period. The distance that a sound wave travels in one period is called the wavelength. Wavelength is related to the speed at which sound travels and can be calculated by dividing the
- [Lusitanian toadfish](https://dosits.org/galleries/audio-gallery/fishes/lusitanian-toadfish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Lusitanian toadfish Sounds (Halobatrachus didactylus) Description During the breeding season, male Lusitanian toadfish, such as the one shown here (under the rock, in the mud), will build their nests under rocks in shallow waters. They attract females by producing a characteristic advertisement
- [Webinar Archive: Marine Animal Sound Production and Reception](https://dosits.org/decision-makers/webinar-series/webinar-archive-2015-16/webinar-archive-marine-animal-sound-production-and-reception/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Marine Animal Sound Production and Reception – Thursday, December 3, 2015 at noon ET (-5 GMT) Topics: Dr. Clara Amorim , ISPA- Instituto Universitário. Dr. Darlene Ketten Download a webinar outline with associated DOSITS links (PDF, 101 KB) Download a summary of the webinar (PDF, 4.36 MB) Dr. Clara
- [Science Tutorial: How do you characterize sounds?](https://dosits.org/decision-makers/tutorials/science/characterize-sounds/) - Sounds are often described as loud or soft; high-pitched or low-pitched. These words are commonly used to describe, or characterize, how sounds are perceived. Scientists, on the other hand, describe sounds with characteristics that can be measured using instruments. Scientists measure intensity and amplitude, which can be related to the common words loud and soft.
- [Northern Seahorse](https://dosits.org/galleries/audio-gallery/fishes/northern-seahorse/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Northern Seahorse Sounds (Hippocampus erectus) Copyright 2001 SeaWorld Inc. Busch Entertainment Corp. All Rights Reserved. http:/seaworld.org/ Description The northern seahorse occurs along the Atlantic coast of North America mainly from South Carolina to Cape Cod, but is occasionally found as far north as
- [How is sound used to help make long-term measurements of the ocean?](https://dosits.org/people-and-sound/research-ocean-physics/how-is-sound-used-to-help-make-long-term-measurements-of-the-ocean/) - For the past century, most ocean measurements have been made from research vessels. Small groups of scientists and technicians made measurements during research expeditions lasting for a month or so, and then returned home to analyze the data that had been collected. Although much has been learned about the ocean using this approach, it is
- [Baiji, Yangtze River Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/baiji-yangtze-river-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Baiji Sounds (Lipotes vexillifer) Description The baiji is a freshwater dolphin found only in the Yangtze River, China. It is pale blue to gray on its dorsal (back) side and white on its ventral (belly) side. It has a low, triangular
- [Dusky Damselfish](https://dosits.org/galleries/audio-gallery/fishes/dusky-damselfish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Dusky Damselfish Sounds (Stegastes adustus) Description Courtesy of Prof. Brad Rence, Department of Biology, Lawrence University, Appleton, WI 54912. The dusky damselfish is a non-migratory, reef associated species that ranges from Florida to Venezuela. Age at maturity and maximum age are estimated
- [Icebreaker](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/icebreaker/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Icebreaker Sounds Description The U.S. Coast Guard cutter Healy is a United States’ polar icebreaker. The Healy is designed to break a maximum of 1.4m (4.5ft) of ice when running continuously at a speed of 3.5 mph (3 knots) and can operate
- [Technology Tutorial Introduction](https://dosits.org/tutorials/technology/) - People use sound in the ocean for a wide variety of purposes. Many important everyday activities, such as fishing, depend on sound for success. This tutorial introduces a variety of technologies for measuring and employing sound in the ocean. Additional content about how people use sound in the ocean is available in the People and
- [Bubble Curtain](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/bubble-curtain/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bubble Curtain Sounds An active bubble curtain surrounds an offshore pile driving installation. Image courtesy of Georg Nehls. Close-up view of a bubble curtain in operation. One can see the streams of bubbles exiting the hose of the bubble curtain. Image courtesy
- [False Positives and False Negatives](https://dosits.org/science/advanced-topics/statistical-uncertainty/false-positives-and-false-negatives/) - Two types of errors can occur when deciding whether or not the means of two data sets are different. One can conclude that there is a real difference between the means when, in fact, there is not. Scientists call this a false positive. It is also called a Type I error. If one instead concludes that
- [Painted Goby](https://dosits.org/galleries/audio-gallery/fishes/painted-goby/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Painted Goby (Pomatoschistus pictus) The painted goby is a relatively small, benthic fish that is found along sand/gravel bottoms in the Eastern Atlantic Ocean and the Mediterranean Sea. Male gobies produce underwater sounds in association with reproduction and agonistic behaviors. Here, a
- [Commercial Fisher](https://dosits.org/galleries/career-gallery/commercial-fisher/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Commercial fishing is the activity of catching and marketing fish and other seafood for profit. Commercial fishers harvest a wide variety of animals, ranging from tuna, cod, and salmon to shrimp, krill, lobster, crab, clams, and squid.
- [Marine fish communication](https://dosits.org/animals/use-of-sound/marine-fish-communication/) - How do marine fishes communicate using sound? For "communication" to occur between individuals, an intentional signal must be generated by one or more individuals and received and interpreted by one or more recipients. Among the many ways of communicating in aquatic environments, sound is perhaps the most effective, especially over long distances (see Why is
- [Submarine Volcanic Eruptions](https://dosits.org/galleries/audio-gallery/other-natural-sounds/eruptions/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sounds of Submarine Volcanic Eruptions Globe displaying location of the Mariana Arc in the Pacific Ocean (left); seafloor (bathymetric) map of the Northern Mariana Arc (middle); and the Northwest (NW) Rota-1 submarine volcano (right). The seafloor is colored according to depth, with
- [How do marine mammals produce sounds?](https://dosits.org/animals/sound-production/how-do-marine-mammals-produce-sounds/) - Mammalian vocalizations are produced by the actions of the larynx, a set of tissues located in the throat. The larynx contains folds of tissue called the vocal cords (also called vocal folds), which vibrate as air passes from the lungs into the oral cavity (also called the mouth). The shape and tension of the vocal
- [Science Tutorial: Sound Speed](https://dosits.org/decision-makers/tutorials/science/sound-speed/) - We know that sound travels. How fast does it travel? Sound travels about 1500 meters per second in seawater. That's approximately 15 soccer fields end-to-end in one second. Sound travels much more slowly in air, at about 340 meters per second, only 3 soccer fields a second. Unfortunately, the answer is really not quite that
- [Sound Reception](https://dosits.org/animals/sound-reception/) - How do marine animals hear? Many experiments have been done to determine whether marine animals hear underwater. Many species of blind amphibians, reptiles, fishes and mammals are known, but no naturally profoundly deaf vertebrate species have been discovered. Studies have found that some fishes are able to hear while most marine mammals are able to
- [How is active acoustics used in fisheries research and management?](https://dosits.org/people-and-sound/investigate-marine-animals/active-acoustics-fisheries/) - Acoustic surveys are used in the monitoring and management of many fish species, including herrings, anchovies, sardines, Atlantic cod, and walleye pollock. Fisheries scientists use active acoustics to estimate fish biomass and abundance (stock assessment); evaluate spatial and temporal distributions; and measure size distributions and [glossary_exclude]population [/glossary_exclude]structure. In addition, these methods can also be used
- [Indo-Pacific Humpback Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/indo-pacific-humpback-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Indo-Pacific Humpback Dolphin (Sousa chinensis) Description Humpback dolphins are found in tropical to temperate, coastal waters of the eastern Atlantic, Indian, and western Pacific oceans. There are four recognized species: S. teuszii, Atlantic humpback dolphin; S. plumbea, Indian Ocean humpback dolphin; S.
- [Killer Whale, Orca](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/killer-whale-orca/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Orca Sounds (Orcinus orca) Description Three killer whales in Johnston Straight, Vancouver, BC. Copyright Tom Kieckhefer. The orca or “killer whale” is found throughout the ocean, from the arctic to the antarctic. These odontocetes are easily identified by their striking black and white
- [Pantropical Spotted Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/pantropical-spotted-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Pantropical Spotted Dolphin (Stenella attenuata) Description Pantropical spotted dolphin and calf. At birth, these dolphins do not have spots; they develop as they age. The species can be distinguished by the dark coloration (“cape”) on their backs and their slender white-tipped beak.
- [Rough-toothed dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/rough-toothed-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Rough-toothed dolphin Sounds (Steno bredanensis) Description Rough-toothed dolphin (front) and bottlenose dolphin (back). The rough-toothed dolphin is very distinct with a long, smooth head and narrow beak. On average, these dolphins reach a length of 2.6 m (8.5 ft) and weight of
- [White-sided Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/white-sided-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 White-sided Dolphin Sounds (Lagenorhynchus spp.) Description Pacific white-sided dolphin. Copyright Tom Kieckhefer The white-sided dolphin is easy to identify with its short, distinct beak and black back with striking light-gray sides and pearl-white belly. The Atlantic white-sided dolphin (Lagenorhynchus acutus) also has
- [Noise Field in the Arctic](https://dosits.org/science/sounds-in-the-sea/noise-field-in-the-arctic/) - The Arctic Ocean can have a wide range of ambient noise conditions, from some of the quietest to some of the loudest in the ocean. Under an ice-covered ocean with calm wind conditions, the ambient noise can be very low. When sea ice deforms or fractures due to wind, waves, or currents, it can produce
- [Hearing in Amphibious Marine Mammals](https://dosits.org/animals/sound-reception/marine-mammals-hear/hearing-pinnipeds/) - Amphibious marine mammals consist of the pinnipeds (sea lions and fur seals, Family Otariidae; true seals, Family Phocidae; and walruses, Family Odobenidae), sea otters (Family Mustelidae), and polar bears (Family Ursidae). All spend time on land as well as in the water. Consequently, their ears need to function both in air and under water[ref]Wartzok, D.,
- [ATOC Transmission](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/atoc-transmission/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 ATOC Transmission Sounds Description ATOC HX-554 acoustic source (75 Hz) on the DSVSS Laney Chouest ready for deployment off Kauai during July, 1997. The acoustic source is a large ceramic cylinder mounted on a frame. Electrical current passed through the cylinder will cause
- [How is sound used to research wind energy?](https://dosits.org/people-and-sound/examine-the-earth/how-is-sound-used-to-research-wind-energy/) - Wind energy is increasingly being used as an alternative energy source. As wind turbines have moved from land into ocean waters, sound is being used to find the best location for offshore wind farms. The potential effects on the environment and marine life of the sound generated by the construction and operation of wind farms
- [How is sound used to measure rainfall over the ocean?](https://dosits.org/people-and-sound/study-weather/how-is-sound-used-to-measure-rainfall-over-the-ocean/) - Rain falling on the ocean makes a loud and distinctive sound that can be used to detect and measure rain at sea. Heavy rain can increase noise levels by up to 35 db across a broad range of frequencies (from roughly 1000 Hz to greater than 50,000 Hz). (What are common underwater sounds?) Extreme
- [Rainfall](https://dosits.org/galleries/audio-gallery/other-natural-sounds/rainfall/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sounds of Rainfall Description Very large raindrops splashing on the ocean surface during an experiment at Kwajalein Atoll in the central Pacific Ocean in 1998. Photo by Jeffrey A. Nystuen, Applied Physics Laboratory, University of Washington. Rain falling on the ocean makes
- [Acoustic Rain Gauge (ARG)](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/acoustic-rain-gauge-arg/) - Rain is one of the most important components of weather and climate. Improved understanding of the global pattern of rainfall is needed to improve weather and climate forecasting. Information on rainfall over the ocean helps meteorologists, oceanographers, and climatologists. Rainfall is difficult to measure over the ocean. The rain gauges commonly used on land collect water
- [Hearing in Land Mammals](https://dosits.org/animals/sound-reception/marine-mammals-hear/land-mammals/) - In order to understand how marine mammals hear sound, it is helpful to understand the mechanisms by which terrestrial mammals hear sound on land. There are many similarities in the basic hearing processes in marine mammals and terrestrial mammals. We will use the human ear as a model for terrestrial ears. Although there are differences
- [Hearing in Cetaceans and Sirenians, the Fully Aquatic Ear](https://dosits.org/animals/sound-reception/marine-mammals-hear/hearing-in-cetaceans/) - The most drastic changes in auditory systems between terrestrial mammals (see Hearing in Land Mammals) and marine mammals can be found in the cetaceans (whales, dolphins and porpoises) and the sirenians (manatees and dugongs). There are even significant differences between the ears of cetaceans and those of pinnipeds (seals, sea lions, and walruses) (see Hearing
- [How do aquatic birds hear?](https://dosits.org/animals/sound-reception/how-do-aquatic-birds-hear/) - In-air hearing sensitivities have been measured for many species of birds. Sound provides birds with information for individual recognition, as well as foraging and predator avoidance cues. However, diving birds often live in hard-to-study areas, and thus, data on the hearing abilities of aquatic birds, especially measurements of their underwater hearing, is lacking. Over 800
- [DOSITS Videos](https://dosits.org/resources/resource-categories/dosits-videos/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 The videos in the tabs below were developed as brief introductions to some of the most commonly requested material on DOSITS. Below each video there is a list of key topics with associated links to DOSITS content for more in-depth material and
- [How do marine mammals hear?](https://dosits.org/animals/sound-reception/marine-mammals-hear/) - Hearing is the detection of sound. Both modern land mammals, including humans, and marine mammals evolved from ancestors that had air-adapted ears. So, many of the structures of the ear in both land and marine mammals are similar. Some marine mammals that live exclusively in water, like whales and manatees, hear very well in water
- [Red Drum](https://dosits.org/galleries/audio-gallery/fishes/red-drum/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Red Drum Sounds (Sciaenops ocellatus) Description Red drum are one of the most recreationally sought-after fish, especially in the South Atlantic and Gulf of Mexico. In order to better manage the fishery, scientists use passive acoustic surveys to listen for drumming sounds
- [New Zealand Bigeye](https://dosits.org/galleries/audio-gallery/fishes/new-zealand-bigeye/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 New Zealand Bigeye (Pempheris adspersa) Description Like other members of the sweeper (Pempheridae) family, New Zealand bigeyes have a deeply keeled and compressed body, with big eyes. These small fish are active sound producers in reef environments. Image credit: FishBase New Zealand
- [Marine Seismologist](https://dosits.org/galleries/career-gallery/marine-seismologist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Seismologists are geologists who specialize in studying seismic waves in the Earth to understand Earth structure. Earthquakes produce seismic waves. Different materials and different layers of the Earth have properties that cause changes in the way seismic
- [Determine if a sound affects a marine animal](https://dosits.org/animals/effects-of-sound/determine-if-a-sound-affects-a-marine-animal/) - How do you determine if a sound affects a marine animal? There are many factors that influence whether a sound source affects any marine animal. How loud the source is, what frequencies it transmits, where it will be used, and what species might be in the area are all factors that need to be assessed.
- [Tutorial: How do you determine if a sound affects a marine animal?](https://dosits.org/tutorials/effects-introduction/determine/) - Highlights: Determining Effects Ecological risk assessment involves defining the problem; that is, determining what might cause ecological effects. Then, an estimate of the probability of being exposed to the problem and the type of potential ecological effects are used to estimate the risk. An example of the risk of the North Pacific Acoustic Laboratory source
- [Effects Tutorial Introduction](https://dosits.org/tutorials/effects-introduction/) - This tutorial will introduce you to the topics and content available on the DOSITS web site involving the effects of underwater sound on marine animals. It is suitable for the general public. Advanced science content is available throughout the site. Please refer to Advanced Topics in the main site navigation bar. Sounds produced by marine
- [Determine if a Sound Affects a Marine Animal Tutorial Introduction](https://dosits.org/decision-makers/tutorials/determine-affects/) - This tutorial is designed for a decision maker to get the basics of how you can determine if a sound affects a marine animal. The user can proceed from one topic to the next in sequence or jump to a topics of special interest. The DOSITS pages contain additional content that may be of particular
- [Ocean Engineer](https://dosits.org/galleries/career-gallery/ocean-engineer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Ocean engineering is a combination of mechanical, electrical, civil, acoustical, and chemical engineering, coupled with a basic understanding of how the oceans work. Ocean engineers design, build, test, and refine instrumentation and equipment that can operate in
- [Locating Sources of Sound](https://dosits.org/galleries/technology-gallery/locating-objects-by-listening-to-their-sounds/)
- [How is sound used to study undersea earthquakes?](https://dosits.org/people-and-sound/examine-the-earth/earthquakes/) - It is important to know when and where earthquakes occur and their magnitude. Earthquakes are typically detected, measured, and located by seismometers on land. However, for submarine earthquakes (earthquakes with an epicenter under the ocean), land-based seismometers may not provide good coverage for detection and measurement. Smaller earthquakes far away from land may go undetected
- [Masking in Fishes](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-fishes/masking-in-fishes/) - Both natural (e.g., snapping shrimp) and anthropogenic(e.g., shipping noise) sound sources can increase the level of background or ambient noise in the environment. Masking occurs when noise interferes with a marine animal's ability to hear a sound of interest. The significance of the masking effect is influenced by the amount of time that the noise
- [Behavioral Changes in Fishes](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-fishes/behavioral-changes-in-fishes/) - Fishes use sound to find prey, avoid predators, and find and communicate with mates (see How do fish communicate using sound? and How do fish use or make sounds when feeding?). Studies that investigate the effects of sound on fishes have been limited. Most fish experiments have been conducted in the laboratory where conditions can
- [Tutorial: Fishes - Masking](https://dosits.org/decision-makers/tutorials/effects/fishes-masking/) - Both natural (e.g., snapping shrimp) and anthropogenic(e.g., shipping noise) sound sources can increase the level of background or ambient noise in the environment. Masking occurs when noise interferes with a marine animal's ability to hear a sound of interest. The significance of the masking effect is influenced by the amount of time that the noise
- [Tutorial: Fishes - Behavioral Change](https://dosits.org/decision-makers/tutorials/effects/fishes-behavioral/) - Fishes use sound to find prey, avoid predators, and find and communicate with mates (see How do fish communicate using sound? and How do fish use or make sounds when feeding?). Studies that investigate the effects of sound on fishes have been limited. Most fish experiments have been conducted in the laboratory where conditions can
- [Tutorial: Hearing Loss](https://dosits.org/tutorials/effects-introduction/tutorial-hearing-loss/) - Highlights: Hearing Loss Loss of hearing from exposure to sound may be a temporary or permanent condition. The extent to which hearing loss occurs depends on a number of variables including the frequency and level of the sound, duration of exposure, and the health of the organism. The amount of data on hearing loss in
- [Tutorial: Physiological Stress](https://dosits.org/tutorials/effects-introduction/tutorial-physiological-stress/) - Highlights: Physiological Stress Humans and other organisms exposed to sound may show changes in stress levels. Physiological stress responses in fishes to anthropogenic sounds have not been documented in the wild and have only been directly studied in two laboratory experiments. Physiological stress responses in marine mammals to anthropogenic sound have not yet been documented.
- [How will ocean acidification affect ocean sound levels?](https://dosits.org/science/sounds-in-the-sea/how-will-ocean-acidification-affect-ocean-sound-levels/) - The amount of carbon dioxide in the atmosphere has increased since the mid- 19th century, the beginning of the Industrial Age. The burning of fossil fuels (oil, coal, and natural gas) and wood produces carbon dioxide gas. The increased use of fossil fuels has produced a rise in atmospheric carbon dioxide levels. This has resulted
- [How do sea turtles hear?](https://dosits.org/animals/sound-reception/how-do-sea-turtles-hear/) - Sea turtles are found throughout the ocean, except in cold, polar waters. At present, we do not have any reliable underwater recordings of sounds produced by turtles, nor do we know how well most sea turtle species hear sound either in air or underwater. Like all turtles, sea turtles lay eggs on land. Mating takes
- [Geophysicist](https://dosits.org/galleries/career-gallery/geophysicist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description A geophysicist studies Earth’s structure and properties. Geophysicists use a variety of methods, but often use gravity, magnetic, and seismic methods. Geophysicists apply their work to many different types of study. Some are finding energy resources such
- [Dr. Miller](https://dosits.org/galleries/scientist-gallery/miller/) - Watch the interview with Dr. Jim Miller Download the Miller interview transcript (PDF) About Dr. Miller Dr. Jim Miller is a professor of ocean engineering at the University of Rhode Island. His research specializes in using underwater sound to study the structure of ocean temperatures and seafloor sediments. Dr. Miller has used this expertise
- [Forward Looking Sonar](https://dosits.org/galleries/technology-gallery/locating-objects-using-sonar/forward-looking-sonar/) - Forward-looking sonar systems are designed for surface ship navigation and obstacle avoidance. These systems are mounted on the bow of the vessel. Although these sonar systems are primarily used in shallow water navigation, they may also be useful in reducing the likelihood of hazardous disasters such oil spills, reef groundings, and whale strikes. The FarSounder sonar detects
- [Underwater Acoustic Cameras](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/underwater-acoustic-cameras/) - Traditional sonar-based systems, such as side-scan sonar and echosounders, operate at long ranges and great depths, but they do not have sufficient resolution to provide the detail required for some applications. Optical imaging systems are effective over short distances where there is sufficient light and clarity. Acoustic cameras use acoustic lenses and a high-frequency transducer array
- [Underwater GPS](https://dosits.org/galleries/technology-gallery/navigation-technology/underwater-gps/) - The global positioning system (GPS) is commonly used on land and in the air to obtain position and timing information. However, the radio frequencies used by GPS cannot penetrate in seawater, requiring a different system for underwater positioning. This information is useful to a variety of ships, automated vehicles, and even individuals. One solution is
- [How is sound used to monitor nuclear testing?](https://dosits.org/people-and-sound/national-defense/how-is-sound-used-to-monitor-nuclear-testing/) - The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosions on Earth whether for military or for peaceful purposes. The CTBT includes an extensive International Monitoring System (IMS) to verify compliance with the treaty. The IMS is a network of over 300 monitoring stations, each using one or more of four different techniques designed to detect
- [How is sound used to measure waves in the surf zone?](https://dosits.org/people-and-sound/research-ocean-physics/how-is-sound-used-to-measure-waves-in-the-surf-zone/) - Waves generated in distant storms roll across the ocean, eventually reaching shore. As the water becomes shallow, the waves break, spraying foam and running up on the beach. Nearby beaches can have very different kinds of surf. For example, Black’s Beach, near San Diego, is a world-renowned surfing spot with powerful waves, while just a
- [How is sound used to measure wind over the ocean?](https://dosits.org/people-and-sound/study-weather/how-is-sound-used-to-measure-wind-over-the-ocean/) - Wind blowing over the ocean generates waves. When these waves become large enough, they break, producing sound under water. Ocean noise levels at frequencies from 200 Hz to 50,000 Hz increase with increasing wind speed. (What are common underwater sounds?) Because the sound produced by breaking waves depends on wind speed, it can be used
- [WOTAN: “Wind Observations Through Ambient Noise”](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/wotan/) - Wind is difficult to measure over the ocean. Wind gauges (anemometers) have to be mounted on surface buoys or ships that pitch and heave in response to ocean waves. The picture below shows one example of a buoy system that measures wind data for climate models. Buoys and ships distort the winds that the anemometers
- [Ichthyologist](https://dosits.org/galleries/career-gallery/ichthyologist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Ichthyology is the branch of biology devoted to the study of fishes. Scientists have described over 32,000 living fish species. While a large number of species have been described, new species continue to be discovered each year.
- [Acoustic Current Meters](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/acoustic-current-meters/) - An acoustic current meter is a set of transducers fixed in a frame. Acoustic current meters are used to measure the velocity and direction of currents and waves. They do this using a technique called "reciprocal transmission." A typical acoustic current meter will transmit a 1
- [Decision Makers Effects of Sound Tutorial Introduction](https://dosits.org/decision-makers/tutorials/effects/) - Potential effects of sound on marine animals How can anthropogenic (man-made) sound affect marine animals? Much attention has recently been focused on anthropogenic sources of sound in the ocean and their potentially harmful effects. Many factors determine whether a sound may impact any marine animal: sound characteristics, such as level, frequency, and duration; animal-dependent features,
- [Acoustic Release](https://dosits.org/galleries/technology-gallery/basic-technology/acoustic-release/) - An acoustic release is used for the recovery of valuable underwater equipment. The release will hold onto the anchor of a buoyant instrument until it is commanded to release it. An acoustic release has the ability to both receive and transmit signals to a surface instrument. It uses battery power and is typically designed to last for
- [Decision Makers Sound Source Tutorial Introduction](https://dosits.org/decision-makers/tutorials/sound-source/) - This tutorial is designed for a decision maker to learn the basics about anthropogenic sound sources in the marine environment. The user can proceed from one topic to the next in sequence or jump to a topics of special interest. The ocean is full of both natural and anthropogenic sources of sound (see What are common underwater sounds?).
- [Tutorial: Where are marine animals likely to be located relative to the source?](https://dosits.org/decision-makers/tutorials/determine-affects/location-of-animals/) - To determine where are marine animals likely to be located relative to a sound source, scientists consider how the animals are spread throughout the area. The first question is whether or not a particular species is found in the area at the time of year that the source is being used. For species that might
- [Science Tutorial: How are sounds viewed and analyzed?](https://dosits.org/decision-makers/tutorials/science/sounds-viewed/) - Most natural sounds have multiple frequencies and intensities that change over time. Scientists and musicians often use graphics to display the components present in a sound. Throughout this website, visualizations are used to help describe sound. In the Audio Gallery, for example, each sound may be displayed as an animated frequency spectrum, a waveform
- [Physiological Stress](https://dosits.org/animals/effects-of-sound/potential-effects-of-sound-on-marine-fishes/physiological-stress/) - There is increasing interest on the part of both the general public and scientific community about the impacts of sound on animals that result in physiological stress. Imagine a loud firecracker going off near you. Your heart rate increases and your body produces chemicals in response to this potential threat. Other animals may show similar
- [Tutorial: Fishes - Physiological Stress](https://dosits.org/decision-makers/tutorials/effects/fishes-stress/) - There is increasing interest on the part of both the general public and scientific community about the impacts of sound on animals that result in physiological stress. Imagine a loud firecracker going off near you. Your heart rate increases and your body produces chemicals in response to this potential threat. Other animals may show similar
- [Tutorial: Echosounders](https://dosits.org/decision-makers/tutorials/sound-source/echosounders/) - Echosounders are a type of sonar commonly used for a variety of tasks, including navigation, measuring bottom depth, and detecting schools of fish and plankton. Single beam echosounders emit a pulse of sound in a narrow cone (2°-12°). Another type of echosounder, multibeam sonar, was developed to produce more detailed maps of the seafloor. These
- [Tutorial: Seismic Airgun](https://dosits.org/decision-makers/tutorials/sound-source/seismic-airgun/) - Seismic airguns are used primarily to examine the layers of the seafloor to study Earth’s history or locate subsea oil and gas deposits. Airguns rapidly release compressed air, causing a bubble to be formed. The formation of the bubble produces a loud sound that travels through the water to the ocean floor. Some of the sound energy
- [Deep-Sea Biologist](https://dosits.org/galleries/career-gallery/deep-sea-biologist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Over 70% of the earth is covered by ocean, and the deep-sea habitat is largely unexplored. Deep-sea biologists are, therefore, scientists and underwater explorers. The deep-sea is defined as the part of the ocean below 200 m
- [Underwater Gliders](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/underwater-gliders/) - Ocean gliders are autonomous vehicles that can operate in all weather conditions, for long time periods, and in remote locations. They move slowly, at about 0.50 knots (about 25 cm/s), and with little noise because they do not have a standard engine or propeller. Gliders can be equipped with a variety of oceanographic sensors, and are frequently
- [How is sound used to communicate underwater?](https://dosits.org/people-and-sound/communication/how-is-sound-used-to-communicate-underwater/) - Have you ever tried talking to your friends underwater? If so, you have discovered that it didn't work very well. Even though sound travels well in water, our vocal cords are not designed to generate underwater sound. How, then, can people use sound to communicate underwater? Scuba divers are trained to use hand signals to
- [Explosive Sound Sources](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/explosive-sound-sources/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Explosive Sound Sources Description A 0.82-kg (1.8-lb) SUS (Signal, Underwater Sound) explosive charge being launched by Dr. Peter Worcester from the R/V Oceanus in 1979 for underwater acoustic research. Underwater explosions generate high-intensity impulsive signals that may be used for research. Some
- [Weakfish](https://dosits.org/galleries/audio-gallery/fishes/weakfish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Weakfish Sounds (Cynoscion regalis) Description Courtesy of Don Flescher This species inhabits coastal and offshore waters of the Atlantic ranging from Cape Cod, Massachusetts to Florida. Northward seasonal migrations to spawning and feeding areas occur along the coast during the spring followed by
- [Striped Searobin](https://dosits.org/galleries/audio-gallery/fishes/striped-searobin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Striped Searobin Sounds (Prionotus evolans) Description Courtesy of Don Flescher The striped searobin occurs along the Western Atlantic coast from Nova Scotia to Florida, although it is rare north of Cape Cod. It primarily inhabits sandy bottoms within estuaries and nearshore waters
- [Stoplight Parrotfish](https://dosits.org/galleries/audio-gallery/fishes/stoplight-parrotfish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Stoplight Parrotfish Sounds (Sparisoma viride) Description Copyright 2002 Wayne & Karen/The Ocean Adventure, http://www.theoceanadventure.com. This species occurs in the Western Atlantic from southern Florida throughout the Caribbean to Brazil, in waters associated with coral reefs. They ares strictly diurnal, sleeping during the
- [Silver Perch](https://dosits.org/galleries/audio-gallery/fishes/silver-perch/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Silver Perch Sounds (Bairdiella chrysoura) Description Silver perch illustration. Copyright Diane Rome Peebles This species occurs in coastal waters from New York to the Gulf of Mexico and is commonly found over sandy or muddy bottoms. Spawning takes place during the spring
- [Hardhead Sea Catfish](https://dosits.org/galleries/audio-gallery/fishes/hardhead-sea-catfish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Hardhead Sea Catfish Sounds (Ariopsis felis) Description Courtesy of Don Flescher. The Hardhead Catfish ranges from Massachusetts to southern Mexico and is common over muddy or sandy bottoms of bays and shallow coastal waters. Spawning occurs in back bays during the spring
- [Spotted Seatrout](https://dosits.org/galleries/audio-gallery/fishes/spotted-seatrout/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Spotted Seatrout Sounds (Cynoscion nebulosus) Description Spotted Seatrout illustration. Copyright Diane Rome Peebles The spotted seatrout ranges from Massachusetts to the Yucatan Peninsula, primarily inhabiting estuaries, lagoons, and inshore waters. This species tolerates a wide range of salinities and is often closely
- [Sand Seatrout](https://dosits.org/galleries/audio-gallery/fishes/sand-seatrout/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sand Seatrout Sounds (Cynoscion arenarius) Description Sand seatrout illustration. Copyright Diane Rome Peebles This species occurs only in the Gulf of Mexico. It is however closely related to the weakfish (Cynoscion regalis) and studies have indicated that these may be slightly different
- [Rock Hind](https://dosits.org/galleries/audio-gallery/fishes/rock-hind/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Rock Hind Sounds (Epinephelus adscensionis) Description Copyright Peter Wirtz, biomar@dragoeiro.uma.pt This species inhabits rocky reefs and occurs off Massachusetts and Bermuda through the Caribbean to Brazil. It is also reported in the Eastern Atlantic around the Ascension and St. Helena islands. Due to
- [Red Grouper](https://dosits.org/galleries/audio-gallery/fishes/red-grouper/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Red Grouper Sounds (Epinephelus morio) Description Red grouper, Epinephelus morio, are dark reddish brown graded to pink in color with occasional white spots or blotches on their bodies. They can be distinguished by their large dorsal fin, which has dark edges (as
- [Plainfin Midshipman](https://dosits.org/galleries/audio-gallery/fishes/plainfin-midshipman/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Plainfin Midshipman Sounds (Porichthys notatus) Description Male plainfin midshipman (Porichthys notatus) excavate den-like nests (above) and produce a loud, droning hum during mating season. Photo by Janna Nichols, www.pnwscuba.com. For years, houseboat residents in Sausalito, CA, complained about a droning hum from
- [Oyster Toadfish](https://dosits.org/galleries/audio-gallery/fishes/oyster-toadfish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Oyster Toadfish Sounds (Opsanus tau) Photo from NOAA, Credit: Andrew David, NOAA/NMFS/SEFSC Panama City; Lance Horn, UNCW/NURC – Phantom II ROV operator Description The oyster toadfish is a bottom dwelling species which occurs along the east coast of North America from
- [Longhorn Sculpin](https://dosits.org/galleries/audio-gallery/fishes/longhorn-sculpin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Longhorn Sculpin Sounds (Myoxocephalus octodecemspinosus) Description Courtesy of Don Flescher The longhorn sculpin is a bottom dwelling species that ranges from Newfoundland to Virginia. Commonly found in harbors and shallow coastal waters during the warmer months, a seasonal migration to deeper waters
- [Garibaldi](https://dosits.org/galleries/audio-gallery/fishes/garibaldi/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Garibaldi Sounds (Hypsypops rubicunda) Description Courtesy of Robert Fenner Garibaldi inhabit rocky substrate and kelp forests from Monterey Bay, California, to the southern tip of Baja, Mexico. It is the largest member in its family (Pomacentridae), commonly known as damselfishes, growing to
- [Clownfish](https://dosits.org/galleries/audio-gallery/fishes/clownfish/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Clownfish Sounds (Amphipiron sp.) Description Clownfish are tropical fishes that live in small, social groups in association with sea anemones (the above shows a common clownfish, Amphiprion ocellaris, in the sea anemone, Heteractis magnifica). “Chirp” and “pop” sounds are produced during agonistic
- [Bluestriped Grunt](https://dosits.org/galleries/audio-gallery/fishes/bluestriped-grunt/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bluestriped Grunt Sounds (Haemulon sciurus) Description Courtesy of John E. Randall The bluestriped grunt ranges from Florida to Brazil including the Gulf of Mexico and Caribbean. Adults are found inhabiting coral and rocky reefs where they are active nocturnal predators of crustaceans, bivalves,
- [Black Drum](https://dosits.org/galleries/audio-gallery/fishes/black-drum/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Black Drum Sounds (Pogonias cromis) Description Black drum illustration. Copyright Diane Rome Peebles The black drum ranges from Massachusetts to Argentina occurring predominately in inshore waters and estuaries. Adults and juveniles are most often found over muddy bottoms of deeper channeled areas
- [Bigeye Scad](https://dosits.org/galleries/audio-gallery/fishes/bigeye-scad/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Bigeye Scad Sounds (Selar crumenophthalmus) Description Courtesy of John E. Randall The bigeye scad is found in clear oceanic tropical waters worldwide. Occurring in schools as large as hundreds of thousands of individuals, it is a highly commercial species. The life of
- [Barred Grunt](https://dosits.org/galleries/audio-gallery/fishes/barred-grunt/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Barred Grunt Sounds (Conodon nobilis) Description Courtesy of Alfredo Cavalho Filho, alfie@telnet.com.br The barred grunt occurs from the northern Gulf of Mexico through the Caribbean to Brazil. Adults inhabit deeper waters (up to 100 m) over rock or coral bottoms during the
- [Atlantic Croaker](https://dosits.org/galleries/audio-gallery/fishes/atlantic-croaker/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Atlantic Croaker Sounds (Micropogon undulatus) Description Courtesy of Don Flescher The Atlantic croaker ranges from Massachusetts to northern Mexico, however it is less common north of New Jersey and south of central Florida. Adults spend the spring and summer months in estuaries
- [Hydrothermal vents](https://dosits.org/galleries/audio-gallery/other-natural-sounds/hydrothermal-vents/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Hydrothermal Vents Description The black smoker vent, Sully, located approximately 2200 m below the sea surface, within the Main Endeavour vent field on the Juan de Fuca Ridge (in the NE Pacific Ocean). Shown here is the hydrophone system used (in 2004)
- [ROV Pilot/Technician](https://dosits.org/galleries/career-gallery/rov-pilottechnician/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Remotely operated vehicles (ROVs), are underwater robots that are tethered to a ship and piloted by a crew onboard the vessel. The tether delivers power to the vehicle and data and video images from the vehicle back
- [How is sound used to study the distribution of marine fishes?](https://dosits.org/people-and-sound/investigate-marine-animals/how-is-sound-used-to-study-the-distribution-of-marine-fishes/) - Many fishes use sound to attract mates for courtship and spawning. Typically it is the males that produce species-specific low frequency (
- [How do fish produce sounds?](https://dosits.org/animals/sound-production/how-do-fish-produce-sounds/) - Fishes produce different types of sounds using different mechanisms and for different reasons. Sounds (vocalizations) may be intentionally produced as signals to predators or competitors, to attract mates, or as a fright response. Sounds are also produced unintentionally including those made as a by-product of feeding or swimming. The three main ways fishes produce sounds
- [Dredging](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/dredging/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Dredging Sounds Description This diagram shows a suction hopper dredger, which works by sucking a mixture of dredged material and water from the seabed through a suction pipe and depositing dredged materials in an onboard hopper. Image credit: United States Government Accountability Office
- [Physical Oceanographer](https://dosits.org/galleries/career-gallery/physical-oceanographer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Physical oceanography is a sub-discipline of oceanography that involves the study of waves, tides, and currents; the ocean-atmosphere relationship that influences weather and climate; and the transmission of light and sound in the oceans. The scales of
- [Biological Oceanographer](https://dosits.org/galleries/career-gallery/biological-oceanographer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Biological oceanography is the study of life histories of marine organisms, their relationships to one another, how they interact with and adapt to their environment, and the processes that govern their distribution in the ocean. Work in
- [How is sound used to measure currents in the ocean?](https://dosits.org/people-and-sound/research-ocean-physics/how-is-sound-used-to-measure-currents-in-the-ocean/) - Currents are commonly measured with sound. There are several different ways to measure currents with sound. An instrument called an Acoustic Doppler Current Profiler or ADCP is often used to measure the current in specific places like shipping channels, rivers and streams, and at buoys. They are also called Acoustic Doppler Profilers (ADP). ADCPs can
- [ADCP (Acoustic Doppler Current Profiler)](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/adcp/) - The Doppler effect is a change in frequency of a sound due to motion of the source of sound or motion of the listener. In the animation below, the sound source is moving toward Observer B and away from observer A. Observer B will hear a higher frequency sound and Observer A will hear a lower frequency sound.
- [What happens when sound pressures are large?](https://dosits.org/science/sound/what-happens-when-sound-pressures-are-large/) - Sources of sound such as airguns, explosives, and electric spark systems can create large underwater sound pressures. In these cases, simple descriptions of sound waves in terms of their frequency, wavelength, and amplitude are no longer adequate. Other phenomena can occur, including harmonic distortion, shock waves, and cavitation. Harmonic Distortion The waveform of a high amplitude
- [Introduction to Signal Levels](https://dosits.org/science/advanced-topics/introduction-to-signal-levels/) - Sounds travels as a wave. The amplitude of the wave is related to the amount of acoustic energy it carries, or how loud the sound will appear to be. As the amplitude of the sound wave increases, the sound is perceived to be louder. There are several different ways to describe the amplitude of a
- [Echosounder](https://dosits.org/galleries/technology-gallery/observing-the-sea-floor/echosounder/) - The most common system for measuring water depth, and preventing collisions with unseen underwater rocks, reefs, etc., is the echosounder. These sonar systems use a transducer that is usually mounted on the bottom of a ship. Sound pulses are sent from the transducer straight down into the water. The sound reflects off the seafloor and returns to the transducer.
- [DOSITS Publications](https://dosits.org/resources/resource-categories/dosits-publications/) - Discovery of Sound in the Sea Booklet The Discovery of Sound in the Sea Booklet is a 16 page publication based on the DOSITS website. It contains information about the importance of sound in the ocean, the science of sound in the ocean, how people and animal use sound in the ocean and the effect
- [Plankton Biologist](https://dosits.org/galleries/career-gallery/plankton-biologist/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Plankton are relatively small organisms whose movements are dominated by currents, though many can swim. They come in all shapes and sizes, the smallest of which are the bacteria, which are too small to be seen without
- [Mechanical Engineer](https://dosits.org/galleries/career-gallery/mechanical-engineer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Mechanical engineering is a broad field of engineering that involves converting scientific concepts into real-world applications. Mechanical engineers apply the principles of engineering, physics and materials science to design, develop, and build mechanical devices, often related to
- [Electrical Engineer](https://dosits.org/galleries/career-gallery/electrical-engineer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics, and electromagnetism. It covers a wide range of subfields including electronics, digital computers, power engineering, telecommunications, control systems, and
- [How is sound used to study underwater volcanoes?](https://dosits.org/people-and-sound/examine-the-earth/volcanoes/) - Underwater volcanic eruptions can be hard to detect and observe. Volcanic eruptions produce earthquakes that are typically detected and measured by seismometers on land. Smaller underwater volcanic eruptions that are far away from land will go undetected by land-based seismometers. When a volcano erupts underwater, it will produce acoustic energy in two ways. First, as
- [Projector (sound source)](https://dosits.org/galleries/technology-gallery/basic-technology/projector-sound-source/) - Just as a loudspeaker is used to produce sound in air, an acoustic projector or sound source is used to generate sound underwater. Loudspeakers convert electrical signals into sound in air. Similarly, acoustic projectors convert electrical signals into sound in water. (See How are sounds made?). Underwater sound sources (may also be called transducers) can be built in a
- [Marine Lawyer](https://dosits.org/galleries/career-gallery/marine-lawyer/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Return to Career Gallery Description Marine law is a body of laws and policies that govern ocean and coastal resources and their use. This may include environmental and marine resource conservation, shipping, marine fisheries, navigation, salvage, and other maritime activities. Marine lawyers
- [Side Scan Sonar](https://dosits.org/galleries/technology-gallery/observing-the-sea-floor/side-scan-sonar/) - One of the best systems for imaging large areas of the ocean floor is side scan sonar. The basic concept is much the same as the basic echosounder; however, side scan sonar instruments are towed behind ships and often called "towfish" or tow vehicles. This technology uses a specially shaped acoustic beam, which pulses out 90
- [How is sound used to identify fish?](https://dosits.org/people-and-sound/fishing/how-is-sound-used-to-identify-fish/) - Experienced fishermen can use fish finders to identify particular species of fishes. As a fish moves through the sonar beam of a fish finder, a mark specific to that fish species appears on the chart display. To determine what species of fish produces what kinds of marks, a fishermen must be familiar with the area
- [Visual Observations](https://dosits.org/animals/effects-of-sound/measure-marine-mammals-reaction-to-sound/visual-observations/) - Visual observations of marine mammals made during large-scale surveys or associated with a specific research project can provide detailed information on the behavior, movement, and abundance of these animals in the wild. Scientists can compare baseline measurements obtained during "control" conditions to those obtained under experimental conditions, when sound is being transmitted. Changes in the
- [Webinar Archive: Potential Effects of Sound on Fishes](https://dosits.org/decision-makers/webinar-series/webinar-archive-2015-16/webinar-archive-potential-effects-of-sound-on-fishes/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Potential Effects of Sound on Marine Fishes – Tuesday, May 10, 2016 at 12:00pm ET Dr. Arthur Popper, University of Maryland Dr. Anthony Hawkins, Environmental Research Institute Download the Potential Effects of Sound on Marine Fishes Webinar topic outline with associated DOSITS links (PDF, 75 KB) Download
- [Webinar Archive: Potential Effects of Sound on Marine Mammals](https://dosits.org/decision-makers/webinar-series/webinar-archive-2015-16/webinar-archive-potential-effects-of-sound-on-marine-mammals/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Potential Effects of Sound on Marine Mammals – Wednesday, March 16, 2016 at 12:00pm ET Dr. Dorian Houser, National Marine Mammal Foundation Dr. Brandon Southall, Southall Environmental Associates, Inc. Download the Potential Effects of Sound on Marine Mammals Webinar topic outline with links (PDF, 82 KB) Download
- [Webinar Archive: Science of Sound](https://dosits.org/decision-makers/webinar-series/webinar-archive-2015-16/webinar-archive-science-of-sound/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Science of Sound Webinar – Friday, November 13, 2015 at 12:00pm ET Topics: Sound movement and sound measurement – Dr. Kathleen Vigness-Raposa, Marine Acoustics, Inc. Ocean noise variability and noise budgets – Dr. James Miller, University of Rhode Island Download the Webinar topic outline
- [Webinar Archive: Summary and Questions](https://dosits.org/decision-makers/webinar-series/webinar-archive-2015-16/webinar-archive-summary-and-questions/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Webinar Archive: Summary and Questions – Thursday, June 16, 2016 at 12:00pm ET A brief summary of the DOSITS webinar series and topics covered will be followed by panel of the previous webinar speakers who will answer questions submitted in advance as well as
- [Dr. Au](https://dosits.org/galleries/scientist-gallery/au/) - Watch the interview with Dr. Whitlow Au Download the interview transcript (PDF) About Dr. Au Dr. Whitlow Au is the Chief Scientist for the Marine Mammal Research Program at the Hawaii Institute of Marine Biology. Dr. Au has studied the mesopelagic boundary community and the acoustics of snapping shrimp, but his primary research is sound production
- [DOSITS Power Points](https://dosits.org/resources/resource-categories/dosits-power-points/) - PowerPoints Designed for Educators The PowerPoint presentations downloaded from the DOSITS website are free to be used in an educational setting. However, they may not be redistributed or reused without permission. This includes posting on any other web pages (including personal or school web pages) or redistribution in any electronic or print medium. If you
- [Dr. Benoit-Bird](https://dosits.org/galleries/scientist-gallery/benoit-bird/) - Watch the interview with Dr. Kelly Benoit-Bird Download the Benoit-Bird interview transcript (PDF) About Dr. Benoit-Bird Dr. Kelly Benoit-Bird is a Senior Scientist at the Monterey Bay Aquarium Research Institute. Dr. Benoit-Bird’s research uses underwater sound to observe how animals ranging in size from nearly microscopic zooplankton to sperm whales interact with each other
- [Dr. Ketten](https://dosits.org/galleries/scientist-gallery/ketten/) - Watch the interview with Dr. Darlene Ketten Download the interview transcript (PDF) About Dr. Ketten Dr. Darlene Ketten is a scientist with Woods Hole Oceanographic Institution's Biology Department and Harvard Medical School's Department of Otology and Laryngology. Her research focuses on the physical shape and function of the hearing and sound producing organs of
- [Tutorial: Measure Currents](https://dosits.org/tutorials/technology/currents/) - Currents are commonly measured with sound. There are several different ways to measure currents with sound. An instrument called an Acoustic Doppler Current Profiler or ADCP is often used to measure the current in specific places like shipping channels, rivers and streams, and at buoys. They are also called Acoustic Doppler
- [Tutorial: Measure Water Depth](https://dosits.org/tutorials/technology/tutorial-measure-water-depth/) - The depths of the ocean have been charted since the early days of sailing using a method called sounding which used a weight on the end of a rope to estimate water depth. The invention of sonar changed the way that the seafloor is mapped. A combined transmitter and receiver, called a transducer, sends a sound pulse straight
- [Tutorial: Sonar](https://dosits.org/tutorials/technology/tutorial-sonar/) - Sonar (sound navigation and ranging) is a technology that uses acoustical waves to sense the location of objects in the ocean. The simplest sonar devices send out a sound pulse from a transducer, and then precisely measure the time it takes for the sound pulses to be reflected back to the transducer. The distance to an
- [Tutorial: Find Objects on the Sea Floor](https://dosits.org/tutorials/technology/find-objects/) - Sonar is used to find objects on the bottom of the ocean. Side scan sonar is one method used to look at the detail of the ocean floor. Side scan sonar instruments are towed behind ships and often called towfish or tow vehicles. The instrument sends out a sonar signal in pulses at right angles to the direction
- [Tutorial: Communicate Underwater](https://dosits.org/tutorials/technology/communicate/) - Have you ever tried talking to your friends underwater? If so, you have discovered that it didn't work very well. Even though sound travels well in water, our vocal cords are not designed to generate underwater sound. How, then, can people use sound to communicate underwater? Scuba divers are trained to use hand signals to
- [Tutorial: Find Fish](https://dosits.org/tutorials/technology/find-fish/) - Fish finding sonar systems assist fishermen and scientists when trying to locate and identify fish underwater. These sonar units operate very similar to other types of sonar. A transducer, attached or towed by a boat, sends out an acoustic signal. This signal will reflect off the air in the swim bladder of a fish, if it has one, or the
- [Tutorial: Measure Temperature](https://dosits.org/tutorials/technology/temperature/) - The speed of sound in water depends on the water properties of temperature, salinity and pressure (directly related to the depth). A typical speed of sound in water near the ocean surface is about 1520 meters per second. That is more than 4 times faster than the speed of sound in air. The speed of sound in
- [Tutorial: Study the Sea Floor](https://dosits.org/tutorials/technology/tutorial-study-the-sea-floor/) - At the bottom of the ocean, there are layers of sediments that contain information about the Earth's history. Sound is used to map and characterize these sediment layers. Sound is used to select the precise locations for coring or drilling sediment samples to study the history of Earth's climate and ocean. Scientists also use sound
- [Tutorial: Behavioral Changes](https://dosits.org/tutorials/effects-introduction/behavioral-changes/) - Highlights: Behavioral Changes An animal's behavioral response depends on a number of factors, such as hearing sensitivity, tolerance to noise, exposure to the same noise in the past, behavior at the time of exposure, age, sex, and group composition. Some marine animal responses to sound are momentary inconsequential reactions, such as the turn of a
- [Tutorial: Masking](https://dosits.org/tutorials/effects-introduction/tutorial-masking/) - Highlights: Masking Masking occurs when a loud sound drowns out a softer sound or when noise is at the same frequency as a sound signal. This is of particular concern to marine animals when the noise is at frequencies similar to those of biologically important signals, such as mating calls. Because of the widespread nature
- [Effects Tutorial Overview](https://dosits.org/tutorials/effects-introduction/overview/) - Scientists suggest that increased background noise and specific sound sources might impact marine animals in several ways. The following sections discuss the effects on marine animals that have been documented in the scientific literature. These effects include: behavioral responses, such as changes in movement, breathing patterns, and vocalizations; masking; hearing loss; physiological stress; and strandings. Although the
- [Waves on Beach](https://dosits.org/galleries/audio-gallery/other-natural-sounds/waves-on-beach/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sound of Waves on Beach Description Breaking wave on a beach. Surface waves can be caused by several different sources, such as passing boats, wind, and rain. Most of the sound of breaking waves is radiated from bubbles trapped under water at
- [Iceberg Collisions](https://dosits.org/galleries/audio-gallery/other-natural-sounds/iceberg-collisions/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sounds of Iceberg Collisions Description A massive iceberg (known as B-15) broke off the Ross Ice Shelf in Antarctica in mid-March 2000, show here with satellite images. Top left image: March 3, 2000, before the calving; Top right image: March 17, 2000,
- [Acoustic Tomographic Mooring](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/acoustic-tomographic-mooring/) - Acoustic tomography uses the travel time of sound in the ocean to measure the temperature of the ocean over large areas. Scientists use acoustic tomographic moorings to send and receive sounds. By measuring the travel time of sound between two moorings, scientists can calculate the temperature of the ocean over the area through which the
- [Inverted Echosounders](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/inverted-echosounders/) - An echo sounder is typically mounted or towed by a boat, and is used to measure the seafloor by sending pinging noises to the seabed and listening for the echoes. An inverted echo sounder (IES) uses the same technique, however it is reversed. An IES is mounted on the seafloor and sends pings to the ocean surface.
- [How is sound used to measure the upper ocean?](https://dosits.org/people-and-sound/research-ocean-physics/how-is-sound-used-to-measure-the-upper-ocean/) - Measuring the processes at the sea surface and the region immediately below it is important for both practical and scientific reasons. Large, steep waves can be hazardous to offshore structures, such as oil platforms. Offshore structures and buoys must be designed to survive the largest waves that are likely to occur. Bubbles created by breaking
- [Projector Array](https://dosits.org/galleries/technology-gallery/basic-technology/projector-array/) - A non-directional projector (sound source) is one that transmits sound equally in all directions. A directional projector is designed to transmit sound primarily in selected directions. Examples of directional projectors are echosounders and side scan sonars. Echosounders that are used to measure ocean depth are designed to point down toward the seafloor (see Echosounder). Side
- [Fish Finding Sonar](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/fish-finding-sonar/) - Fish finding sonar systems assist fishermen and scientists when trying to locate and identify fish underwater. These sonar units operate very similar to other types of sonar. A transducer, attached or towed by a boat, sends out an acoustic signal. This signal will reflect off the air in the swim bladder of a fish, if it has one, or the fish itself.
- [Between World War I and World War II: The 1920s and 1930s](https://dosits.org/people-and-sound/history-of-underwater-acoustics/between-world-war-i-and-world-war-ii-the-1920s-and-1930s/) - The period between WWI and World War II (WWII) was a time of increased discovery about underwater acoustics. Scientists were beginning to understand some fundamental concepts about sound propagation, and underwater sound was being used to explore the ocean and its inhabitants. For example, shortly after WWI, H. Lichte, a German scientist, developed a theory
- [SOFAR Floats](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/sofar-floats/) - Since the mid 1970s, Sound Fixing And Ranging (SOFAR) floats have been used to measure and track oceanic currents. These floats send out acoustic pulses, typically at 260 Hz, and moored listening stations at known locations receive the sound signals. Using time of arrival of the signal at three or more hydrophones, the position of
- [Hydrophone Arrays](https://dosits.org/galleries/technology-gallery/basic-technology/hydrophone-arrays/) - A hydrophone array is made up of a number of hydrophones placed in known locations. These hydrophones maybe placed in a line on the seafloor, moored in a vertical line in the water column, or towed in a horizontal line behind a boat or ship, for example. Sound arriving at the array from a distant source, such as a
- [Acoustic Monitoring](https://dosits.org/animals/effects-of-sound/measure-marine-mammals-reaction-to-sound/acoustic-monitoring/) - Acoustic monitoring of animal vocalizations is often used in conjunction with visual observations and surveys. Passive acoustic monitoring is a powerful tool compared to visual surveys because sound can travel great distances underwater. This not only allows for the detection of marine animals outside the visual range of the observers, but it can also provide information
- [Statistical vs. Biological Significance](https://dosits.org/science/advanced-topics/statistical-uncertainty/statistical-vs-biological-significance/) - The conclusion that there is a statistically significant difference indicates only that the difference is unlikely to have occurred by chance. It does not [glossary_exclude]mean[/glossary_exclude] that the difference is necessarily large, important, or significant in the common meaning of the word. An example is the measurements made to determine whether or not Surveillance Towed Array
- [How are sounds made?](https://dosits.org/science/sound/how-are-sounds-made/) - Sound is created by a vibrating object. For example, when a drum is struck, the flexible skin (sometimes called a membrane) of the drum vibrates. The compression and expansion of the air on either side of the vibrating membrane produces differences in air pressure. The pressure differences generate a sound wave that propagates outward from
- [Group-specific Vocalizations](https://dosits.org/animals/use-of-sound/marine-mammal-communication/group-specific-vocalizations/) - Marine mammals that live together have developed a communication system that allows them to maintain or regain contact with group members over long distances. Individual animals often leave the group during feeding and are able to reunite with their group members by producing and recognizing vocalizations that are specific to their group. Group-specific vocalizations also allow
- [Vocalizations Associated with Reproduction](https://dosits.org/animals/use-of-sound/marine-mammal-communication/vocalizations-associated-with-reproduction/) - Marine mammals produce many kinds of sounds that are associated with reproduction. For example, males of some species produce vocalizations to compete with other males or to attract females. In the latter case, some females, such as female elephant seals, compare males based on vocalizations. In other species, like the North Atlantic right whale, females
- [How does marine life affect ocean sound levels?](https://dosits.org/science/sounds-in-the-sea/how-does-marine-life-affect-ocean-sound-levels/) - The sounds produced by marine animals are many and varied. Marine mammals, such as blue whales and harbor porpoise, produce sounds over a wide frequency range, from less than 10 Hz to over 100,000 Hz, depending on the species of marine mammal. Many fish, such as the oyster toadfish and plainfin midshipman, and some marine
- [Measure marine mammal's reaction to sound](https://dosits.org/animals/effects-of-sound/measure-marine-mammals-reaction-to-sound/) - How do you measure a marine mammal's reaction to sound? Although the effects of noise on people have been studied extensively, only recently has a substantial amount of effort been devoted to studying the effects of sound on animals, particularly marine mammals. A variety of methods are being applied or developed to help measure the
- [Decision Makers Science of Sound Tutorial Introduction](https://dosits.org/decision-makers/tutorials/science/) - This tutorial is designed for a decision maker to get the basics of the science of sound in the marine environment. The user can proceed from one topic to the next in sequence or jump to a topics of special interest. The DOSITS website contain additional content that may be of particular interest in the Science
- [How does sound in air differ from sound in water?](https://dosits.org/science/sounds-in-the-sea/how-does-sound-in-air-differ-from-sound-in-water/) - Sound in water and sound in air are both waves that move similarly and can be characterized the same way. Sound waves can travel through any substance, including gases (such as air), liquids (such as water), and solids (such as the seafloor). Did you know that sound cannot exist if it doesn't have something to
- [Science Tutorial: How does sound in air differ from sound in water?](https://dosits.org/decision-makers/tutorials/science/air-water/) - Sound in water and sound in air are both waves that move similarly and can be characterized the same way. Sound waves can travel through any substance, including gases (such as air), liquids (such as water), and solids (such as the seafloor). Did you know that sound cannot exist if it doesn't have something to
- [Tutorial: Can Animals Sense These Sounds Part I](https://dosits.org/decision-makers/tutorials/determine-affects/animals-sense-sound-1/) - Marine Mammals How do marine mammals hear? Hearing is the detection of sound. Both modern land mammals, including humans, and marine mammals evolved from ancestors that had air-adapted ears. So, many of the structures of the ear in both land and marine mammals are similar. Some marine mammals that live exclusively in water, like whales
- [Tutorial: Mammals - Hearing loss](https://dosits.org/decision-makers/tutorials/effects/mammals-hearing-loss/) - The basic mechanism of sound detection is the same in all mammals, whether they live on land or in the sea. Sound waves are transformed to neural impulses in the inner ear, which are interpreted by the brain as sounds (see How do marine mammals hear sounds? ). Exposure to loud sounds can interfere with
- [Spiny Lobster](https://dosits.org/galleries/audio-gallery/marine-invertebrates/spiny-lobster/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Spiny Lobster Sounds (Palinurus sp) Description The common spiny lobster.Courtesy of Sheila Patek Spiny lobsters are marine invertebrates that are found throughout the world. These clawless lobsters belong to the Palinuridae family and are best characterized by their two long antennae. Many arthropods are
- [Finless Porpoise](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/finless-porpoise/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Finless Porpoise Sounds (Neophocaena phocaenoides) Description As its name suggests, the finless porpoise lacks a dorsal fin. Instead the animal possesses a ridge, or “groove”, that runs down the middle of its back (as seen above). This mother and calf pair is
- [Tagging Studies](https://dosits.org/animals/effects-of-sound/measure-marine-mammals-reaction-to-sound/tagging-studies/) - Visual observations provide information about the behavior of animals when they are at the surface, but how do scientists study animals' behavior underwater? One way is to attach instruments, called tags, to marine animals. The tags provide information on what the animals are doing when they are underwater. They also allow scientists to track the
- [Tutorial: Fishes - Hearing Loss](https://dosits.org/decision-makers/tutorials/effects/fishes-hearing-loss/) - Exposure to intense sounds can cause a permanent or temporary hearing loss. Some anthropogenic sounds may cause temporary threshold shift (TTS), depending on a number of variables including the frequency and intensity of the sound, duration of exposure, etc. (see How do you determine if a sound affects a marine animal?). The physiological basis for
- [Science Tutorial: Sound Pressure Levels and Sound Exposure Levels](https://dosits.org/decision-makers/tutorials/science/spl-sel/) - Regulators use sound pressure levels (SPLs) and sound exposure levels (SELs) to characterize potential effects of sound on marine animals. Sound pressure level (SPL) is a means of characterizing the amplitude of a sound. There are several ways sound pressure can be measured. The most common of these are the root-mean-square (rms) pressure, the peak
- [Tutorials](https://dosits.org/tutorials/) - DOSITS Tutorials The Tutorials are designed to give an introduction to the core topics of one section of the DOSITS web site. For additional information on a topic, explore that section of the DOSITS website. Science of Sound Tutorial Effects of Sound Tutorial Technology Tutorial
- [Tutorial: Sound Levels at Distance and Depth](https://dosits.org/decision-makers/tutorials/determine-affects/sound-at-distance/) - The first step in determining if a sound source might impact marine animals is to make an estimate of the sound field around the source. A source's sound field is the level of sound at different distances and depths as the sound travels away from the source. There are many models that predict how sound travels away
- [Geophone](https://dosits.org/galleries/technology-gallery/basic-technology/geophone/) - Sound waves are characterized by compression and expansion of the medium as sound energy moves through it. This represents the pressure component of sound. At the same time, there is also back and forth motion of the particles making up the medium. Particle motion is described by displacement, velocity, and acceleration. Geophones are devices that generate electric signals proportional to the particle
- [Articles](https://dosits.org/resources/resource-categories/articles/) - Articles listed here are related to topics on the DOSITS site or about the DOSITS site. Underwater Acoustics for Everyone by Kathleen J. Vigness-Raposa, Gail Scowcroft, Holly Morin and Christopher Knowlton in Acoustics Today, Vol. 10 Issue 2, Spring 2014 Sonars and Strandings: Are Beaked Whales the Aquatic Acoustic Canary? by Darlene R. Ketten in
- [Introduction to Decibels](https://dosits.org/science/advanced-topics/introduction-to-decibels/) - What is a dB? The intensity of a sound wave is the average amount of energy transmitted per unit time through a unit area in a specified direction. The amount of energy per unit time is [glossary_exclude]power[/glossary_exclude], and intensity is therefore the amount of[glossary_exclude] power[/glossary_exclude] transmitted through a unit area in a specified direction. [glossary_exclude]Power[/glossary_exclude]
- [Marine fish and invertebrates feeding](https://dosits.org/animals/use-of-sound/marine-fish-and-invertebrates-feeding/) - How do marine fish and invertebrates use or make sound when feeding? The most common sounds associated with feeding fish are simply a result of chewing and ingesting food items. The diets of many fishes include the skeletons of crustaceans and other fishes, and the calcium carbonate skeleton of corals. Crunching sounds are produced when
- [Scattering](https://dosits.org/science/movement/how-does-sound-move/scattering/) - Seawater has bubbles, suspended particles, organisms, and many other things that affect sound as it travels through seawater it. The use of a flashlight can be used as an example to illustrate what happens. Most of the time, the flashlight creates a circle of light on objects at which it is pointed. However, what happens
- [Northern Fur Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/northern-fur-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Northern Fur Seal Sounds (Callorhinus ursinus) Description Northern Fur Seals. Photos courtesy of Stephen Insley, University of Victoria. Northern Fur Seals are found in the North Pacific. Their primary rookeries are in the Bering Sea, with small numbers also breeding on San Miguel
- [Harbor Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/harbor-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Harbor Seal Sounds (Phoca vitulina) Description Close-up of harbor seal head. Copyright Tom Kieckhefer The harbor seal is probably the most widely known seal and is also referred to as the common seal. When hauled out on rocks or ledges, they often
- [Common Dolphin](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/common-dolphin/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Common Dolphin Sounds (Delphinus spp.) Description Two common dolphins. Photo courtesy of NOAA Fisheries. The short-beaked common dolphin is the most numerous dolphin species in the offshore waters of the Atlantic, Pacific, and Indian Oceans. The long-beaked common dolphin has only recently
- [Ribbon Seal](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/ribbon-seal/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Ribbon Seal Sounds (Histriophoca fasciata) Description Ribbon seals are found in the northern Pacific Ocean and are often seen hauled out on sea ice during the late winter and spring. Adult seals have a distinct pattern of light, ribbon-like bands that encircle the
- [Lightning](https://dosits.org/galleries/audio-gallery/other-natural-sounds/lightning/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Sound of Lightning Description Photo courtesy of Moonraker Australia Lightning strikes the coastal ocean at a rate of about 2 strikes per square kilometer per year. Lightning in the open ocean is rare. Most people are very familiar with lightning because lightning
- [Earthquake](https://dosits.org/galleries/audio-gallery/other-natural-sounds/earthquake/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Earthquake Sounds Description The trace of an earthquake from a seismometer on land. Image modified from the USGS. Undersea earthquakes make low frequency sounds from the movement of the seafloor. The sounds they make can be heard far away from the earthquake
- [Science Tutorial: Sound Absorption](https://dosits.org/decision-makers/tutorials/science/absorption/) - You have heard the word "absorb" in many contexts. Think of a paper towel commercial. They advertise, "This towel is more absorbent than the average towel." Or think of a sponge. If you spill grape juice, you clean it up by wiping a wet sponge over the grape juice spill. The sponge has just absorbed
- [Science Tutorial: Sound Spreading](https://dosits.org/decision-makers/tutorials/science/science-tutorial-sound-spreading/) - If we think of a wave spreading out from a rock that is thrown into a pond, the further from the source, the bigger the circle formed by the wave. As the circle gets bigger, its total length (circumference) also gets bigger. Spreading loss occurs because the total amount of energy in a wave remains
- [Science Tutorial: Frequency](https://dosits.org/decision-makers/tutorials/science/frequency/) - High-pitched or low-pitched refer to the frequency of a sound wave. Because sound travels in a wave, the characteristics that scientists use to describe sound, such as frequency, can be related to a picture of a wave. A wave has a repeating pattern. One complete repetition is called a cycle. The time to complete a
- [Science Tutorial: Amplitude (Intensity)](https://dosits.org/decision-makers/tutorials/science/amplitude/) - A sound wave’s amplitude relates to changes in pressure. The sound is perceived as louder if the amplitude increases, and softer if the amplitude decreases. This is illustrated below. DOSITS short video on amplitude. The amplitude of a wave is related to the amount of energy it carries. A high amplitude wave carries a large
- [Tutorial: Sound Level Exposure](https://dosits.org/decision-makers/tutorials/determine-affects/tutorial-sound-level-exposure/) - What are the sound levels to which the animals are likely to be exposed? The following figure shows the level of sound at different distances and depths as the sound travels away from the ATOC/NPAL source towards the island of Kauai. Sound travels in all directions away from the source, but only the slice related
- [Feature Sound: Waves](https://dosits.org/resources/resource-categories/feature-sounds/waves/) - "Waves are motions that carry energy, but not matter, from one place to another" - that is the definition of a wave from The World Book Encyclopedia. I did a random "man on the street" type of interview and asked people what they thought about the sound of waves and came up with some very
- [Feature Sound: Sounds from Below](https://dosits.org/resources/resource-categories/feature-sounds/sounds-from-below/) - Reva, a newborn humpback whale, enjoyed swimming with his mother and exploring his new surroundings in the Sea of Cortez (Gulf of California). Every sound and flash of light was new to him. Reva noticed that his mother and all the other mothers nearby communicated with each other through a series of groans, wails, and
- [Feature Sound: Snapping Shrimp](https://dosits.org/resources/resource-categories/feature-sounds/snapping-shrimp/) - They sound like a string of firecrackers going off, or a sheet of bubble wrap rapidly being popped. Pound for pound, the worst noisemakers in the sea, their din is so pervasive that submarines have successfully used this racket as cover to confuse enemy sonar. For decades scientists believed the mysterious 'snapping shrimp' made
- [Feature Sound: Ship Noise](https://dosits.org/resources/resource-categories/feature-sounds/ship-noise/) - When I was young, I so wanted to learn how to scuba dive so that I can visit with the whales. At the time I thought that I'd be swimming in the quiet, majestic presence of these mighty creatures. Fortunately, many years later I did learn to scuba dive, but I have yet do
- [Feature Sound: My Life as a Raindrop](https://dosits.org/resources/resource-categories/feature-sounds/raindrop/) - My life begins in a cloud. A cloud contains not only water, but also tiny particles such as dust, smoke and salt. These particles are called condensation nuclei. I wrap myself around one of these tiny particles and depending on its size, I become a droplet ranging anywhere from 0.0001 to 0.005 centimeters in
- [Career Gallery](https://dosits.org/galleries/career-gallery/) - How “Fight or Flight” May Affect Marine Mammal Vocalizations – April 4, 2025 Loading... An ocean-bottom seismometer being deployed. USGS Photograph by Uri ten Brink. A female bottle nose dolphin performs her daily exercises while her trainer supervises. Image credit U.S. Navy. Brennan Phillips piloting a Remotely Operated Vehicle from the control room on a
- [Feature Sound: Lightning Striking the Sea!](https://dosits.org/resources/resource-categories/feature-sounds/lightning/) - Imagine a rod of fire moving at a very high rate of speed causing the air around it to be heated to extreme temperatures of 50,000° F. to 54,000° F. As the charge travels through the air, the dramatic heating expands the air causing hydrogen atoms to explode. The shock waves from the explosions
- [Feature Sound: Haunting Refrains (Humpback whale)](https://dosits.org/resources/resource-categories/feature-sounds/haunting-refrains-humpback/) - Miles' trumpet brewing Sketches of echoing Elephant wails Through the depths Howling lone wolf calls Reeking in the mystery Of a cow's moo-o-o Reverberating Bird cries Harmoniously enveloped In sopranoish choral chants.... .....longings....... ......sustained haunting refrains Sung by the humpback whale Diving, rolling and swimming Through its subterranean jungle Humpback whale songs can
- [Feature Sound: Bottlenose Dolphin](https://dosits.org/resources/resource-categories/feature-sounds/bottlenose-dolphin/) - The Atlantic bottlenose dolphins are small cetaceans that have a long, beaklike snout, a falcate (sickle-shaped) dorsal fin, and sharp teeth. They are Odontoceti (toothed whales) and have one blowhole. These dolphins live in small groups called pods. The bottlenose dolphin has been the subject of much study. Their clicks, quacks and whistles have
- [Featured Sound: Beluga Whale](https://dosits.org/resources/resource-categories/feature-sounds/beluga/) - Well, hello there!! My name is Delphinapterus leucas. My friends just call me Beluga. That comes from the Russian word Belukha which means white. I live in a pod, or a group of about 10 beluga whales, in the arctic and subartic areas of the world during most of the year. During the summer
- [Feature Sound: Acoustic Thermometry of Ocean Climate (ATOC)](https://dosits.org/resources/resource-categories/feature-sounds/atoc/) - The ocean is vast. If we wanted to find the average temperature of the Pacific Ocean between California and Hawaii using traditional methods (dropping a thermometer over the deck of a ship as you steam from San Francisco to Maui) it would require huge amounts of time and money. Science has come up with
- [Feature Sounds](https://dosits.org/resources/resource-categories/feature-sounds/)
- [DOSITS 10th Anniversary Symposium](https://dosits.org/resources/resource-categories/meetings/dosits-10th-anniversary-symposium/) - SOUND IN THE SEA Recent Discoveries and Applications A symposium on the 10th anniversary of the Discovery of Sound in the Sea (DOSITS) project to highlight current advances in underwater acoustics 2013 ICA/ASA/CAA Meeting Tuesday, June 4, 2013 7:30pm-9:30pm Intercontinental Hotel Montreal, CanadaSponsored by the Acoustical Society of America The Discovery of
- [Meetings](https://dosits.org/resources/resource-categories/meetings/)
- [Decision Maker Tutorials](https://dosits.org/decision-makers/tutorials/)
- [Advanced Topics in Sound](https://dosits.org/science/advanced-topics/)
- [Sound Measurement](https://dosits.org/science/measurement/)
- [Sound Movement](https://dosits.org/science/movement/)
- [Animals and Sound](https://dosits.org/animals/)
- [Science of Sound](https://dosits.org/science/)
- [Sound](https://dosits.org/science/sound/)
- [People and Sound Summary](https://dosits.org/people-and-sound/people-and-sound-summary/)
- [Acoustic Transponders](https://dosits.org/galleries/technology-gallery/navigation-technology/acoustic-transponders/) - Sound is used to precisely navigate underwater. Underwater positioning systems use an acoustic hydrophone or transducer and acoustic transponders. There are several types of acoustic navigation systems, ranging from ultra short baseline to long baseline. Ultra short baseline (USBL) systems are operated from a surface vessel. An acoustic transponder, operating at a set frequency, is attached to the equipment
- [Technology Gallery Summary](https://dosits.org/galleries/technology-gallery/technology-gallery-summary/)
- [Audio Gallery Summary](https://dosits.org/galleries/audio-gallery/audio-gallery-summary/)
- [Animals and Sound Summary](https://dosits.org/animals/animals-and-sound-summary/)
- [Science of Sound Summary](https://dosits.org/science/science-of-sound-summary/)
- [Reference List: Animals and Sound](https://dosits.org/decision-makers/reference-list-animals-and-sound/) - Animals and Sound Suggested Reference List Use of sound Amorim, M.C.P. and Hawkins, A.D. 2000, "Growling for food: acoustic emissions during competitive feeding of the streaked gurnard." Journal of Fish Biology 57,895-907. Boon, P.Y., D.C.J. Yeo, and P.A. Todd. 2009, "Sound production and reception in mangrove crabs Perisesarma spp. (Brachyura: Sesarmidae)." Aquatic Biology. 5, 107-116. Bouwma, P.E. & Herrnkind,
- [Help with PowerPoint Presentations](https://dosits.org/resources/resource-categories/dosits-power-points/help-with-powerpoint-presentations/) - Help With DOSITS Power Points This document gives help for some common issues with the PowerPoint presentations available on the DOSITS website. If your problem is not described here, consult the online help in PowerPoint or the Internet help at Microsoft's web site. The PowerPoint presentations from DOSITS are free to be used in an
- [Resource Categories](https://dosits.org/resources/resource-categories/)
- [Anthropogenic Sounds](https://dosits.org/galleries/audio-gallery/anthropogenic-sounds/)
- [Other Natural Sounds](https://dosits.org/galleries/audio-gallery/other-natural-sounds/)
- [Fishes](https://dosits.org/galleries/audio-gallery/fishes/)
- [Marine Invertebrates](https://dosits.org/galleries/audio-gallery/marine-invertebrates/)
- [Sirenians](https://dosits.org/galleries/audio-gallery/marine-mammals/sirenians/)
- [Pinnipeds](https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/)
- [Toothed Whales](https://dosits.org/galleries/audio-gallery/marine-mammals/toothed-whales/)
- [Baleen Whales](https://dosits.org/galleries/audio-gallery/marine-mammals/baleen-whales/)
- [Marine Mammals](https://dosits.org/galleries/audio-gallery/marine-mammals/)
- [Navigation Technology](https://dosits.org/galleries/technology-gallery/navigation-technology/)
- [Communications Technology](https://dosits.org/galleries/technology-gallery/communications-technology/)
- [Locating Objects Using Sonar](https://dosits.org/galleries/technology-gallery/locating-objects-using-sonar/)
- [Observing and Monitoring Marine Animals](https://dosits.org/galleries/technology-gallery/observing-and-monitoring-marine-animals/)
- [Observing Ocean Currents and Temperature](https://dosits.org/galleries/technology-gallery/observing-ocean-currents-and-temperature/)
- [Observing the Sea Floor](https://dosits.org/galleries/technology-gallery/observing-the-sea-floor/)
- [World War I: 1914-1918](https://dosits.org/people-and-sound/history-of-underwater-acoustics/world-war-i-1914-1918/) - The use of submarines and underwater mines in WWI profoundly influenced the development of underwater acoustics. German submarines (called U-boats) targeted shipping between the United States and Europe, sinking nearly 10 million tons of cargo in two years, severely crippling the U.S. and European Allied Forces’ supply lines. Explosions from contact mines suspended on underwater
- [The First Practical Uses of Underwater Acoustics: The Early 1900s](https://dosits.org/people-and-sound/history-of-underwater-acoustics/the-first-practical-uses-of-underwater-acoustics-the-early-1900s/) - Toward the end of the 1800’s, increasing ship traffic raised concerns about navigation. Additionally, the bright lights and loud sirens emitted from lighthouses and lightships did not travel far enough to warn ships about the dangers of shallow waters and rocks. In 1889, the American Lighthouse Board mentioned an alternative underwater bell and microphone system
- [The Discovery of Underwater Acoustics: Pre-1800s](https://dosits.org/people-and-sound/history-of-underwater-acoustics/the-discovery-of-underwater-acoustics-pre-1800s/) - “If you cause your ship to stop and place the head of a long tube in the water and place the outer extremity to your ear, you will hear ships at a great distance from you.” Leonardo da Vinci, 1490 Aristotle (384–322 BC) was among the first to note that sound could be heard
- [History of Underwater Acoustics](https://dosits.org/people-and-sound/history-of-underwater-acoustics/)
- [National Defense](https://dosits.org/people-and-sound/national-defense/)
- [Study Weather](https://dosits.org/people-and-sound/study-weather/)
- [Investigate Marine Animals](https://dosits.org/people-and-sound/investigate-marine-animals/)
- [Examine the Earth](https://dosits.org/people-and-sound/examine-the-earth/)
- [Research Ocean Physics](https://dosits.org/people-and-sound/research-ocean-physics/)
- [Fishing](https://dosits.org/people-and-sound/fishing/)
- [Navigation](https://dosits.org/people-and-sound/navigation/)
- [Communication](https://dosits.org/people-and-sound/communication/)
- [Marine Mammal Communication](https://dosits.org/animals/use-of-sound/marine-mammal-communication/)
- [Effects of Sound](https://dosits.org/animals/effects-of-sound/)
- [Advanced Topics in Anmials](https://dosits.org/animals/advanced-topics-animals/)
- [Sound Production](https://dosits.org/animals/sound-production/)
- [Importance of Sound](https://dosits.org/animals/importance-of-sound/)
- [Use of Sound](https://dosits.org/animals/use-of-sound/)
- [Sounds in the Sea](https://dosits.org/science/sounds-in-the-sea/)
- [Basic Technology](https://dosits.org/galleries/technology-gallery/basic-technology/)
- [Technology Gallery](https://dosits.org/galleries/technology-gallery/)
- [Scientist Gallery](https://dosits.org/galleries/scientist-gallery/) - ROV Pilot Underwater acoustics is a part of many marine research projects. Some scientists use sound to track ocean currents, identify potential obstacles or quantify fish distributions. Other projects don’t directly use sound, but listen to ocean noise or investigate how marine animals produce and hear sounds. The scientists listed below have given interviews for
- [People and Sound](https://dosits.org/people-and-sound/)
- [Sound Absorption](https://dosits.org/science/movement/why-does-sound-get-weaker-as-it-travels/sound-absorption/) - You have heard the word "absorb" in many contexts. Think of a paper towel commercial. They advertise, "This towel is more absorbent than the average towel." Or think of a sponge. If you spill grape juice, you clean it up by wiping a wet sponge over the grape juice spill. The sponge has just absorbed

## CM Tooltip Glossary Pro

- [Settlement](https://dosits.org/glossary/settlement/) - The process by which some aquatic organisms move or drift through the ocean or freshwater and settle on a substrate as part of their life cycle, e.g., the transformation from a planktonic larval phase in the water column to a stationary, benthic phase.
- [Recruitment](https://dosits.org/glossary/recruitment/) - In population dynamics, the process by which new individuals are added to a population.
- [absorption](https://dosits.org/glossary/absorption/) - The transformation of sound energy into other forms of energy, such as heat, resulting in a decrease of the sound wave’s amplitude as it passes through a medium.
- [ambient sound](https://dosits.org/glossary/ambient-sound/) - Encompasses all sounds that exist in a location at a specific time. Examples of sound sources contributing to ambient sound may include waves, wind, rain, animals, earthquakes, volcanoes, shipping, and airguns. See also ambient noise.
- [wave equation](https://dosits.org/glossary/wave-equation/) - A partial differential equation that describes how a quantity (e.g. pressure) changes over space and across time.
- [goose-beaked whale](https://dosits.org/glossary/goose-beaked-whale/) - Ziphius cavirostris also known as Cuvier's beaked whale
- [continuous wave pulse](https://dosits.org/glossary/continuous-wave-pulse/) - a single frequency tone when referring to sonar signals
- [transducer](https://dosits.org/glossary/transducer/) - a device that converts energy from one form to another. In acoustics, it is often converting between mechanical energy (motion) and acoustic energy, or electrical energy and acoustic energy.
- [synthetic-aperture sonar](https://dosits.org/glossary/synthetic-aperture-sonar/) - Synthetic-aperture sonars combine a number of acoustic pings to form an image with much higher along-track resolution than conventional sonars.
- [saffir-simpson hurricane wind scale](https://dosits.org/glossary/saffir-simpson-hurricane-wind-scale/) - The Saffir–Simpson hurricane wind scale (SSHWS) classifies hurricanes into five categories distinguished by the intensities of their sustained winds. Hurricanes are tropical cyclones in the Western Hemisphere that exceed the intensities of tropical depressions and tropical storms.
- [LIDAR](https://dosits.org/glossary/lidar/) - a remote sensing method using frequencies of light that penetrate water and are used for mapping clear rivers and shallow coastal bathymetry from the air.
- [light detection and ranging](https://dosits.org/glossary/light-detection-and-ranging/) - a remote sensing method using frequencies of light that penetrate water and are used for mapping clear rivers and shallow coastal bathymetry from the air.
- [leachate](https://dosits.org/glossary/leachate/) - liquid that has dissolved or entrained environmentally harmful substances that may then enter the environment.
- [frequency modulation](https://dosits.org/glossary/frequency-modulation/) - variation of the frequency of a carrier wave in accordance with the characteristics of a signal.
- [cSEL](https://dosits.org/glossary/csel/) - measurement of the total energy of a sound event over a specified time period, considering both the intensity and duration of exposure. The measurement is performed on the time series data and is displayed in logarithmic units (e.g., dB SPL).
- [cumulative sound exposure level](https://dosits.org/glossary/cumulative-sound-exposure-level/) - measurement of the total energy of a sound event over a specified time period, considering both the intensity and duration of exposure. The measurement is performed on the time series data and is displayed in logarithmic units (e.g., dB SPL).
- [biofouling](https://dosits.org/glossary/biofouling/) - the accumulation of microorganisms, plants, algae, or small animals on surfaces, causing structural or other functional deficiencies.
- [amplitude modulation](https://dosits.org/glossary/amplitude-modulation/) - the amplitude (signal strength) of a carrier wave is varied in proportion to that of the signal, while the frequency and phase remain constant.
- [ambient noise](https://dosits.org/glossary/ambient-noise/) - background sound in the ocean. Examples of sound sources contributing to ambient noise include waves, wind, rain, shrimp, earthquakes, volcanoes, and distant sources, such as shipping and airguns.
- [Gated Continuous Waves](https://dosits.org/glossary/gated-continuous-waves/) - Simple and good Doppler sensitivity but does not have a high BT.
- [Eigenray](https://dosits.org/glossary/eigenray/) - Propagating rays that connect the sound source and receiver in ray tracing mdoels.
- [Differentiating depth](https://dosits.org/glossary/differentiating-depth/) - Equal to ten acoustic wavelenghts; the water depth, based on the frequency of the signal, that determines whether modeling is ocurring in an acoustically deep or shallow water over space and across time.
- [cylindrical](https://dosits.org/glossary/cylindrical/) - Having straight parallel sides and a circular or oval cross-section; in the shape or form of a cylinder.
- [sinusoid](https://dosits.org/glossary/sinusoid/) - a sine wave; a mathematical curve defined in terms of the sine trigonometric function
- [aliasing](https://dosits.org/glossary/aliasing/) - when an analog signal is not digitally sampled at a high enough rate, the signal that is reconstructed from the digital samples will not match the original signal
- [sine wave](https://dosits.org/glossary/sine-wave/) - a sinusoid; a mathematical curve defined in terms of the sine trigonometric function
- [Nyquist rate](https://dosits.org/glossary/nyquist-rate/) - twice the highest frequency in an analog signal (acoustic signal)
- [sampling frequency](https://dosits.org/glossary/sampling-frequency/) - the number of samples per second; how often a sample is taken
- [digital signal](https://dosits.org/glossary/digital-signal/) - a series of samples to represent a continuous analog signal.
- [analog signal](https://dosits.org/glossary/analog-signal/) - a continuous signal that varies with time based on another quantity; it is analogous to another quantity
- [hair cells](https://dosits.org/glossary/hair-cells/) - mechano-transducers that detect energy or pressure changes. They are complex structures that include a cell body on the surface of a membrane. At the base of the hair cell are one or more neural synapses. On the upper surface of the hair cell are hair-like projections called stereocilia, commonly in bundles. These stereocila bend in
- [epithelium](https://dosits.org/glossary/epithelium/) - a type of body tissue that forms the covering on all internal and external surfaces of he body, lines body cavities and hollow organs, and is the major tissue in glands.
- [myctophid fish](https://dosits.org/glossary/myctophid-fish/) - any of the numerous small, deep-sea fishes of the family Myctophidae that have bioluminescent light organs on the head and sides and that often swim to the surface at night.
- [Deep Scattering Layer (DSL)](https://dosits.org/glossary/deep-scattering-layer-dsl/) - a region in the water column where there is a high density of marine organisms that reflect sound.
- [reference units](https://dosits.org/glossary/reference-units/) - the value against which a relative amount is calculated. For example, a decibel is a relative unit (ratio of measured to reference), therefore a reference unit must be specified to understand the value
- [spectral characteristics](https://dosits.org/glossary/spectral-characteristics/) - the frequency components of an acoustic signal
- [Antarctic Convergence](https://dosits.org/glossary/antarctic-convergence/) - a zone in the Southern Ocean that separates the waters surrounding Antarctica from sub-Antarctic regions. Waters around Antarctica are colder and slightly less saline than north of the convergence zone
- [Franciscana](https://dosits.org/glossary/franciscana/) - Pontoporia blainvillei, Also known as: La Plata dolphin, toninha, cachimbo, boto amarelo
- [sexual dimorphism](https://dosits.org/glossary/sexual-dimorphism/) - distinct difference in size or appearance between male and female sexes of an animal
- [striped cusk eel](https://dosits.org/glossary/striped-cusk-eel/) - Ophidion marginatum
- [Roche’s snake blenny](https://dosits.org/glossary/roches-snake-blenny/) - Ophidion rochei
- [sonic muscle](https://dosits.org/glossary/sonic-muscle/) - a muscle that is attached to the swim bladder. Rapid flexure of the sonic muscle against the swim bladder produces drum-like sounds commonly associated with courtship and spawning behavior.
- [diel](https://dosits.org/glossary/diel/) - having a 24 hour period
- [waveform interval period](https://dosits.org/glossary/sonar-interval-period/) - time between sonar waveforms
- [sonar](https://dosits.org/glossary/sonar/) - an acronym for SOund Navigation And Ranging equipment. Sonar systems use sound waves to detect underwater objects by listening to the returning echoes. The distance to the object or the seafloor can be calculated by measuring the time between when the signal is sent out and when the reflected sound, or echo, is received.
- [nominal](https://dosits.org/glossary/nominal/) - according to plan, usual, or expected.
- [sonar waveform duration](https://dosits.org/glossary/sonar-waveform-duration/) - the length of time of the sonar waveform
- [duty cycle](https://dosits.org/glossary/duty-cycle/) - the time period or fraction of one time period in which a signal or system is active
- [reverberant environment](https://dosits.org/glossary/reverberant-environment/) - an environment with a large amount of reverberation. An environment with a large number of echoes.
- [frequency modulated pulse](https://dosits.org/glossary/frequency-modulated/) - a tone that changes in frequency over its duration. The frequency change can be from lower to higher frequency (upsweep) or from higher to lower frequency (downsweep).
- [sonar waveform](https://dosits.org/glossary/sonar-waveform/) - the combined components of a sonar signal, which includes all the sonar pulses
- [sonar pulse](https://dosits.org/glossary/sonar-pulse/) - each individual component of a sonar signal
- [Mid-frequency Active sonar](https://dosits.org/glossary/mid-frequency-active-sonar/) - A naval sonar system primarily used to detect submarines, defined as a sonar that emits in the frequencies from 1kHz to 10kHz by the U.S. Navy. Often abbreviated MFA.
- [power](https://dosits.org/glossary/power-2/) - the rate at which work is done; the amount of energy transmitted over a given amount of time; or in statistics, the probability of rejecting the null hypothesis in a statistical test when it is false.
- [marine vibroseis](https://dosits.org/glossary/marine-vibroseis/) - a technique for creating a geophysical survey sound source by displacing a volume of water with a vibrating plate or shell to create a pressure wave. Also called a marine vibrator.
- [eDNA](https://dosits.org/glossary/edna/) - organismal DNA that can be found in the environment. Environmental DNA (eDNA) originates from cellular material shed by organisms (via skin, excrement, etc.), which can be collected and monitored using molecular methods.
- [burst pulsed sounds](https://dosits.org/glossary/burst-pulse-sounds/) - a rapid series of broadband clicks similar to those used in echolocation, but with a much shorter interclick interval of 0.5-10ms. Given this very high pulse repetition rate, greater than 300 pulses/second, more clicks are produced per unit time with burst pulsed sounds.
- [slippery dick wrasse](https://dosits.org/glossary/slippery-dick-wrasse/) - Halichoeres bivittatus
- [domino damselfish](https://dosits.org/glossary/domino-damselfish/) - Dascyllus trimaculatus
- [common damselfish](https://dosits.org/glossary/common-damselfish/) - Pomacentrus amboinensis
- [A-weighting](https://dosits.org/glossary/a-weighting/) - the most commonly used frequency weighting function for humans that accounts for the fact that human hearing is less sensitive to low frequencies; units dB(A) or dBA.
- [depredate](https://dosits.org/glossary/depredate/) - the removal and/or damage of netted or hooked fish and bait from fishing gear. Generally, to prey upon, to make a prey of.
- [decibel](https://dosits.org/glossary/decibel/) - a relative unit used to describe sound intensities. Written as dB. See Advanced Topic: Introduction to Decibels.
- [isochronous](https://dosits.org/glossary/isochronous/) - happening at regular intervals
- [sequestration](https://dosits.org/glossary/sequestration/) - the process of depositing carbon from the atmosphere in a pool , or reservoir. In terms of carbon sequestration, it presumes a reservoir that is not easily transferable to the atmosphere or only transfers over a long time period.
- [saturate](https://dosits.org/glossary/saturate/) - when no more of something can be dissolved, or the degree or extent to which something is dissolved or absorbed compared with the maximum possible, usually expressed as a percentage
- [carbon sink](https://dosits.org/glossary/carbon-sink/) - a carbon sink takes up more carbon from the atmosphere than it releases, resulting in a net decrease of carbon in the atmosphere
- [diffuse](https://dosits.org/glossary/diffuse/) - the spreading out of molecules or atoms (or energy), generally away from from higher concentrations
- [patchiness](https://dosits.org/glossary/patchiness/) - degree of irregular, or uneven, appearance or quality.
- [trophic level](https://dosits.org/glossary/trophic-level/) - a particular step or position within a food chain, food web, or ecological pyramid where a group of organisms exist.
- [tropical cyclone](https://dosits.org/glossary/tropical-cyclone/) - a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. These intense circular storms originate over warm tropical oceans.
- [planktivore](https://dosits.org/glossary/planktivore/) - an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton.
- [herbivore](https://dosits.org/glossary/herbivore/) - an organism that feeds mostly on plants.
- [omnivore](https://dosits.org/glossary/omnivore/) - an organism that eats plants and animals.
- [sei whale](https://dosits.org/glossary/sei-whale/) - Balaenoptera borealis
- [tidewater glaciers](https://dosits.org/glossary/tidewater-glaciers/) - valley glaciers that flow all the way down to the ocean.
- [underwater soundscape](https://dosits.org/glossary/underwater-soundscape/) - characterization of the ambient sound in terms of its spatial, temporal, and frequency attributes, and the types of sources contributing to the sound field (ISO Technical Committee on Acoustics, Underwater Acoustics Subcommittee, ISO 18405:2017). Underwater soundscape is sometimes used synonymously with acoustic environment (or ambient sound) to refer to the composite of all sounds in
- [soundscape](https://dosits.org/glossary/soundscape/) - acoustic environment as perceived or experienced and/or understood by a listener. (ISO Technical Committee on Acoustics, Noise Subcommittee, ISO 12913-1:2014).
- [octave band sound](https://dosits.org/glossary/octave-band-noise/) - sound over a range of frequencies where the frequency in Hertz of the upper end of the range is twice the frequency of the lower end.
- [spectral](https://dosits.org/glossary/spectral/) - the frequency composition of sound.
- [Swift scallop](https://dosits.org/glossary/swift-scallop/) - Chlamys swifti
- [Common cockle](https://dosits.org/glossary/common-cockle/) - Cerastoderma edule
- [Pacific oyster](https://dosits.org/glossary/pacific-oyster/) - Magallana gigas
- [mollusks](https://dosits.org/glossary/mollusks/) - invertebrates that possess a soft, unsegmented body and live in aquatic or damp habitats. Many have an external, calcareous shell (although some do not). Phylum Mollusca is the second-largest phylum of invertebrate animals after the arthropods (Arthropoda), and includes gastropods (e.g. snails and slugs), cephalopods (e.g. octopuses), and bivalves (e.g. clams).
- [bivalve](https://dosits.org/glossary/bivalve/) - an aquatic mollusk that has a compressed body enclosed within a hinged shell, such as oysters, clams, mussels, and scallops.
- [longfin squid](https://dosits.org/glossary/longfin-squid/) - Loligo pealeii
- [cephalopod](https://dosits.org/glossary/cephalopod/) - squid, cuttlefish, octopods, and nautilus.
- [statocyst](https://dosits.org/glossary/statocyst/) - a sac-like structure containing a mineralized mass (statolith) in association with numerous sensory cells.
- [annelid](https://dosits.org/glossary/annelid/) - worms or wormlike animals of the phylum Annelida, characterized by an elongated, cylindrical, segmented body with movable bristles (or setae); includes the earthworms, polychaete worms, and leeches.
- [ctenophore](https://dosits.org/glossary/ctenophore/) - gelatinous, aquatic invertebrate also known as a "comb jelly". They use rows of cilia ("combs") to swim. Most species have eight strips, called comb rows, that run the length of their bodies and bear comb-like bands of cilia, called "ctenes". When the cilia beat, those of each comb touch the comb below . The name "ctenophora"
- [coelenterates](https://dosits.org/glossary/coelenterates/) - a group of aquatic invertebrates that includes jellyfishes, corals, and sea anemones. They are distinguished by having a saclike body with a single opening ringed with tentacles.
- [tubercle](https://dosits.org/glossary/tubercle/) - a small rounded projection.
- [cheliped](https://dosits.org/glossary/cheliped/) - one of the pair of legs that bears the large chelae in decapod crustaceans. A male fiddler crab has an enlarged claw or cheliped.
- [chelae](https://dosits.org/glossary/chelae/) - hinged, pincer-like claws at the end of certain limbs of some crustaceans and arachnids (e.g. crabs, lobsters, and scorpions). Typically, chelae are curved and sharply pointed and are used for feeding, defense, and courtship. They can be referred to as claws, nippers, or pincers; legs bearing chelae are called chelipeds.
- [tonal](https://dosits.org/glossary/tonal/) - a sound consisting of a single frequency.
- [Neural impulses](https://dosits.org/glossary/neural-impulses/) - an electrical and chemical signal sent along nerve fibers
- [critical ratio](https://dosits.org/glossary/critical-ratio/) - the ratio, in decibels, of the signal power to the noise power in a 1-Hz band (centered at the [glossary_exclude]test[/glossary_exclude] frequency) required to reliably detect a signal at some predetermined level of correctness
- [power spectral density level](https://dosits.org/glossary/power-spectral-density-level/) - the power present in a signal as a function of frequency, measured in units per Hz.
- [bandpass filter](https://dosits.org/glossary/bandpass-filter/) - a signal processing technique that allows a range of frequencies to be heard, while blocking higher and lower frequencies.
- [critical bandwidth](https://dosits.org/glossary/critical-bandwidth/) - the bandwidth of a masking sound at which the detection threshold of a tone at the center of the masking sound ceases to increase with increasing width of the masking bandwidth; an estimate of the bandwidth of the auditory filter at the center frequency.
- [Frequency selectivity](https://dosits.org/glossary/frequency-selectivity/) - the ability of an animal to discern the frequency of one sound in the presence of sounds of different frequencies.
- [tonotopically organized](https://dosits.org/glossary/tonotopically-organized/) - frequency-dependent resonance, in which the basilar membrane vibrates more near the base with high frequencies, while lower frequencies cause the membrane to vibrate most towards the apex.
- [masking sounds](https://dosits.org/glossary/masking-sounds/) - sounds that compete with sounds of interest for reception and processing in the ear of an animal. Also known as "maskers".
- [acoustic masking](https://dosits.org/glossary/acoustic-masking/) - when sounds (masking sounds or maskers) interfere with an animal’s ability to perceive, detect, or discriminate a different sound.
- [interface wave](https://dosits.org/glossary/interface-wave/) - a type of wave that is only found at the interface between two dissimilar media such as at the boundary of the sea floor and the ocean
- [Infauna](https://dosits.org/glossary/infauna/) - marine animals that live in the seafloor such as clams or worms
- [Terrigenous](https://dosits.org/glossary/terrigenous/) - derived from land, referring to weathered rock grains and minerals
- [Sediment](https://dosits.org/glossary/sediment/) - solid particles of inorganic or organic material deposited in water on the bottom
- [Clay](https://dosits.org/glossary/clay/) - both a grain size (1µm - 3.9 µm) and a type of aluminum silicate mineral
- [Scholte wave](https://dosits.org/glossary/scholte-wave/) - a surface wave causing elliptical motion at the interface. Found at an interface between a solid and an elastic medium such as the seafloor and water. Also called ground roll.
- [Rayleigh wave](https://dosits.org/glossary/rayleigh-wave/) - A Rayleigh wave is a surface wave causing retrograde elliptical particle motion at the surface. Rayleigh waves are one type of seismic wave produced by earthquakes. Found at an interface between a solid and a vacuum or a low-density gas medium such as the Earth’s atmosphere. Also called ground roll.
- [shear wave](https://dosits.org/glossary/shear-wave/) - a transverse wave in the seafloor or solid Earth
- [pressure wave](https://dosits.org/glossary/pressure-wave/) - a longitudinal wave in the seafloor or solid Earth (also called a compression wave)
- [surface wave](https://dosits.org/glossary/surface-wave/) - a sound wave (or seismic wave) that travels only at an interface boundary
- [molt](https://dosits.org/glossary/molt/) - to shed the outer covering, or shell, which is then replaced by a new shell that is produced by the organism
- [porosity](https://dosits.org/glossary/porosity/) - a measure of the pore space in a material, often expressed as a percentage of total volume
- [inhomogeneities](https://dosits.org/glossary/inhomogeneities/) - parts that are not the same as the larger whole or not uniform in composition
- [stratification](https://dosits.org/glossary/stratification/) - separation of water layers based on strong density differences
- [ocean front](https://dosits.org/glossary/ocean-front/) - the interface between two water masses of different physical characteristics
- [bottom reverberation](https://dosits.org/glossary/bottom-reverberation/) - sound scattering that occurs at or near the sea bottom
- [surface reverberation](https://dosits.org/glossary/surface-reverberation/) - sound scattering that occurs on or at the sea surface
- [scatterer](https://dosits.org/glossary/scatterer/) - an object that reflects sound energy, can be a particle in seawater or the sea surface or the seafloor
- [volume reverberation](https://dosits.org/glossary/volume-reverberation/) - sound scattering caused by interactions with marine life, inanimate matter, and inhomogeneities in the water
- [reverberation](https://dosits.org/glossary/reverberation-2/) - the total sound reflected by multiple scatterers
- [acoustic reflex (AR)](https://dosits.org/glossary/acoustic-reflect-ar/) - the contraction of the middle-ear muscles in response to sound stimulation. The reflex decreases the transmission of vibrational energy to the cochlea.
- [efferent](https://dosits.org/glossary/efferent/) - moving or carrying outward or away from a central part. For example: efferent blood vessels carrying blood away from the heart or efferent nerves carrying signals away from the brain.
- [automatic gain control (AGC)](https://dosits.org/glossary/automatic-gain-control-agc/) - a system that automatically controls the increase in the amplitude of an electrical signal. “Gain” controls how loud something is before it goes through any processing.
- [conditioned response](https://dosits.org/glossary/conditioned-response/) - a response that becomes associated with a previously unrelated stimulus as a result of pairing the stimulus with another stimulus normally yielding the response.
- [tone pips](https://dosits.org/glossary/tone-pips/) - acoustic stimuli that are presented as single frequency, pure tone(s).
- [pulse train](https://dosits.org/glossary/pulse-train/) - a repetitive series of short duration, broadband signals that are separated in time by a fixed and often constant interval
- [atmospheric pressure](https://dosits.org/glossary/atmospheric-pressure/) - the force per unit area exerted by the weight of the atmosphere; also known as barometric pressure.
- [barometric pressure](https://dosits.org/glossary/barometric-pressure/) - the force per unit area exerted by the weight of the atmosphere; also known as atmospheric pressure.
- [pressure](https://dosits.org/glossary/pressure/) - the amount of force per unit area measured in units of Pascal (which is defined as 1 Newton acting on an area of 1 square meter).
- [Bryde’s whale](https://dosits.org/glossary/brydes-whale/) - Balaenoptera edeni edeni
- [red hind](https://dosits.org/glossary/red-hind/) - Epinephelus guttatus
- [passive acoustic monitoring (PAM)](https://dosits.org/glossary/passive-acoustic-monitoring-pam/) - observation method where an acoustic device is deployed in the ocean to capture sounds from the surrounding environment (the instrument does not produce any sounds). The sounds received by the instrument are identified and classified. PAM has become an important tool in observing cetaceans, especially deep-diving species.
- [walleye pollock](https://dosits.org/glossary/walleye-pollock/) - Gadus chalcogrammus (also known as Alaska pollock)
- [hake](https://dosits.org/glossary/hake/) - Merluccius merluccius
- [passive acoustics](https://dosits.org/glossary/passive-acoustics/) - listening to sound sources; sound is only received.
- [turbidity](https://dosits.org/glossary/turbidity/) - the measure of relative clarity of a liquid. It is an optical characteristic of water and is a measurement of the amount of light that is scattered by material in the water when a light is shined through the water sample. Turbidity makes water cloudy or opaque. The higher the intensity of scattered light, the
- [autonomous](https://dosits.org/glossary/autonomous/) - existing and/or functioning independently; with regards to ocean-going vehicles, one which travels at the surface or underwater without requiring input from an operator.
- [dialect](https://dosits.org/glossary/dialect/) - vocalizations or calls of cetaceans that are stereotyped, distinctive, and discrete to a particular group or pod.
- [Lombard Effect](https://dosits.org/glossary/lombard-effect/) - the unconscious tendency of a person or animal to raise and/or lower their voice when going from a relatively quiet to a noisy environment and vice versa
- [echolocation](https://dosits.org/glossary/echolocation/) - a process for locating distant or hard-to-see objects using the reflection of sound waves. The distance of objects or depth of the seafloor can be determined by measuring the time it takes for reflected sound waves (echoes) to return to the sound source. Some whales and dolphins use echolocation to identify underwater objects and to
- [stress](https://dosits.org/glossary/stress/) - when an optimal steady state is threatened by internal and/or external forces, and is counteracted by a physiological or biological response (to maintain/establish equilibrium).
- [fertility](https://dosits.org/glossary/fertility/) - the ability to produce offspring; fecundity. Fertility rate is the number of offspring born per mating pair, individual, or population.
- [vital rates](https://dosits.org/glossary/vital-rates/) - factors that determine the abundance or density of a population, including birth rate, death rate, emigration, age structure, and sex ratios. These factors influence population dynamics and allow scientists and managers to track population demographics through time.
- [chronic](https://dosits.org/glossary/chronic/) - developing over an extended period of time and long-lasting. Chronic conditions are long term in nature, and usually have slow to develop symptoms that potentially worsen over time.
- [acute](https://dosits.org/glossary/acute/) - severe condition with a sudden onset.
- [bistatic sonar](https://dosits.org/glossary/bistatic-sonar/) - when the sound source and receiver are located in different places
- [monostatic sonar](https://dosits.org/glossary/monostatic-sonar/) - when the sound source and receiver are located in the same place
- [grazing angle](https://dosits.org/glossary/grazing-angle/) - the angle formed by the incident ray or the reflected ray and the plane(surface).
- [complementary angle](https://dosits.org/glossary/complementary-angle/) - two angles are complementary when they add up to 90°.
- [threshold of hearing](https://dosits.org/glossary/threshold-of-hearing/) - the minimum intensity at which a sound of a specific frequency is reliably detected in absolute quiet conditions. The intensity level varies with frequency. Also called hearing thresholds.
- [hearing threshold](https://dosits.org/glossary/hearing-threshold/) - the minimum intensity at which a sound of a specific frequency is reliably detected in absolute quiet conditions. The intensity level varies with frequency. Also called threshold of hearing.
- [manatee](https://dosits.org/glossary/manatee/) - Large, herbivorous, aquatic mammal that inhabits warm coastal and inland waters of the southeastern U.S., West Indies, northern South America, and West Africa. Manatees have a robust, rounded body, small head, paddle-shaped flippers, and a flattened, rounded tail. The animals are members of the genus Trichechus.
- [masking](https://dosits.org/glossary/masking/) - reduced ability to detect, recognize, or understand sounds of interest because of interference by other sounds
- [Precipitation](https://dosits.org/glossary/24244/) - any liquid or frozen water that forms in the atmosphere (clouds) and falls back to the Earth (e.g. rain, hail, sleet, and snow).
- [bathymetry](https://dosits.org/glossary/bathymetry/) - charting of the sea floor using water depth measurements
- [triangulation](https://dosits.org/glossary/triangulation/) - method for determining the location of a target of interest. Three distances from three known points are measured, and from these distances, a unique point of intersection can determined (this calculation is usually performed by computers). The point of intersection indicates the target's location.
- [utricle](https://dosits.org/glossary/utricle/) - the larger of the two fluid-filled cavities forming part of the inner ear (the other being the sacculus).
- [otolith](https://dosits.org/glossary/otolith/) - small bones in the inner ear which provide balance, and, in fish, aid in hearing
- [characteristic acoustic impedance](https://dosits.org/glossary/characteristic-acoustic-impedance/) - the specific acoustic impedance of a plane wave propagating horizontally.
- [specific acoustic impedance](https://dosits.org/glossary/specific-acoustic-impedance/) - the ratio of acoustic pressure to the associated particle speed in a medium.
- [potential energy](https://dosits.org/glossary/potential-energy/) - the energy possessed by an object as a result of its position relative to other objects, stresses within itself, its electric charge, or other factors.
- [barotrauma](https://dosits.org/glossary/barotrauma/) - The result of an inability to equalize pressures between the environment and an air-filled area of the body. This can happen in air (such as ear discomfort and ear drum injury when planes descend or ascend) or in water (such as injuries to lung tissues or middle ears when scuba diving). Barotrauma typically occurs at
- [blast injury](https://dosits.org/glossary/blast-injury/) - Injuries that occur as a result of an explosion (blast) which produces a shock wave with rapid shifts to extremely high pressures (compression) followed by lower than ambient pressures (rarefaction). These sudden pressure extremes can produce direct physical injury to body tissues or indirect injuries from debris or transport of bodies into other objects. Blast
- [contact calls](https://dosits.org/glossary/contact-calls/) - sounds produced by closely associated conspecifics (individuals of the same species) as a means of keeping in touch. Contact calls are important for individual, mate, and kin recognition as well as group cohesion and movement coordination. A wide variety of social information can be encoded in the acoustic structure of contact calls.
- [tympanic membrane or eardrum](https://dosits.org/glossary/tympanic-membrane-or-eardrum/) - a membrane that separates the outer ear from the middle ear. The eardrum vibrates in response to sound waves and passes the vibrations on to the bones of the middle ear.
- [rise time](https://dosits.org/glossary/rise-time/) - the time it takes for the leading edge of an [acoustic] pulse to rise from its minimum to its maximum value.
- [Risso's dolphin](https://dosits.org/glossary/rissos-dolphin-2/) - Grampus griseus
- [duration](https://dosits.org/glossary/duration/) - the length of a sound in seconds.
- [brisance](https://dosits.org/glossary/brisance/) - the ability to shatter nearby objects because of the rapid release of energy and the rapid increase in pressure by explosives.
- [radionuclide](https://dosits.org/glossary/radionuclide/) - a radioactive atom.
- [Tertiary wave](https://dosits.org/glossary/tertiary-wave-2/) - seismic energy that has been converted into acoustic energy in the ocean. Also a T-wave.
- [ice keel](https://dosits.org/glossary/ice-keel/) - the underwater portion of an ice ridge.
- [attenuate](https://dosits.org/glossary/attenuate/) - reduce the force or effect of; the gradual loss of flux intensity through a medium.
- [bandwidth](https://dosits.org/glossary/bandwidth/) - the frequency span of a signal, calculated as the difference between the highest frequency of a signal and the lowest frequency of a signal.
- [matched filtering](https://dosits.org/glossary/matched-filtering/) - to detect and classify signals of sound sources within acoustic recordings by comparing against known signals (matched-filter processing).
- [matched-filter processing](https://dosits.org/glossary/matched-filter-processing/) - to detect and classify signals of sound sources within acoustic recordings by comparing against known signal (matched filtering).
- [spectrum](https://dosits.org/glossary/spectrum/) - a catalog of the amplitude of a signal as a function of frequency or pitch, with graphics showing low frequencies on the left of the x-axis and high frequencies on the right.
- [chirp](https://dosits.org/glossary/chirp/) - a signal in which the frequency changes with time; the opposite type of signal is a pure-frequency tone where the frequency remains the same throughout the signal.
- [tonotopic organization](https://dosits.org/glossary/tonotopic-organization/) - to be organized by frequency.
- [filtering](https://dosits.org/glossary/filtering/) - a signal processing technique that selects frequencies of interest during the analysis of signals.
- [signal processing](https://dosits.org/glossary/signal-processing-2/) - the analysis of signals to obtain information.
- [substrate](https://dosits.org/glossary/substrate/) - the surface or medium on which an organism lives or grows, or the material on the bottom of the ocean.
- [acoustic lens](https://dosits.org/glossary/acoustic-lens/) - a delay-and-sum beamformer in which the delays and sums are accomplished by the refraction and concentration of acoustic rays induced by the curved surface of the lens.
- [center frequency](https://dosits.org/glossary/center-frequency/) - when describing a sonar system, the frequency with the highest intensity, usually listed as the operating frequency of the sonar.
- [hearing range](https://dosits.org/glossary/hearing-range/) - the range of frequencies the ear of an animal can detect.
- [biomagnification](https://dosits.org/glossary/biomagnification/) - the process by which a compound (such as a pollutant or pesticide) increases its concentration in the tissues of organisms as it travels up the food chain. (also known as bioamplification or biological magnification)
- [demersal](https://dosits.org/glossary/demersal/) - living and/or feeding on or near the bottom of seas or lakes.
- [critically endangered](https://dosits.org/glossary/critically-endangered/) - A category on the IUCN Red List of Threatened Species which indicates a taxon is considered to be facing an extremely high risk of extinction in the wild.
- [pod](https://dosits.org/glossary/pod/) - a social group of whales that are clustered together. Some toothed whales, such as orcas travel in large, sometimes stable pods. They may group together to hunt their prey and/or migrate.
- [fishes](https://dosits.org/glossary/fishes/) - two or more fish species. For example, if you have three fish species in an aquarium (such as a clownfish, damselfish, and goby), you would say "three fishes." If you have three clownfish (all of the same species), you would say "three fish".
- [Great cormorant](https://dosits.org/glossary/great-cormorant/) - Phalacrocroax carbo sinensis
- [African penguin](https://dosits.org/glossary/african-penguin/) - Spheniscus demersus
- [Melon-headed whale](https://dosits.org/glossary/melon-headed-whale/) - Peponocephala electra
- [gray whale](https://dosits.org/glossary/gray-whale/) - Eschrichitus robustus
- [Largemouth bass](https://dosits.org/glossary/largemouth-bass/) - Micropterus salmoides
- [Yellow perch](https://dosits.org/glossary/yellow-perch/) - Perca flavescens
- [Channel catfish](https://dosits.org/glossary/channel-catfish/) - Ictalurus punctatus
- [downsweep](https://dosits.org/glossary/downsweep/) - a signal that decreases in frequency over time.
- [upsweep](https://dosits.org/glossary/upsweep/) - a signal that increases in frequency over time.
- [echosounder](https://dosits.org/glossary/echosounder/) - an instrument that uses sound echoes to determine the water depth. The instrument emits sound waves that travel to the bottom of the ocean and are reflected back. Depth is determined by timing how long it takes the sound pulse to leave the instrument, travel to the seafloor, and return to the receiver on the
- [American paddlefish](https://dosits.org/glossary/american-paddlefish/) - Polyodon spathula
- [pallid sturgeon](https://dosits.org/glossary/pallid-sturgeon/) - Scaphirhynchus albus
- [Atlantic herring](https://dosits.org/glossary/norwegian-herring/) - Clupea harengus
- [impulsive sound](https://dosits.org/glossary/impulsive-sound/) - a broadband signal generated by sound sources such as explosions and airguns in which the sound pressure is very large at the instant of the explosion and then decays rapidly away; the duration of the peak pressure pulse is usually only a few milliseconds.
- [airgun](https://dosits.org/glossary/airgun/) - An airgun is designed to release compressed air, which forms bubbles. The formation of bubbles produces a loud sound that is used to explore the geologic structure of the ocean floor. Airguns primarily produce sound at low frequencies (between 10-500 Hz); however, high frequency noise is also created. A small airgun that releases 0.16 Liters
- [reflection](https://dosits.org/glossary/reflection/) - the deflection of the path of a sound wave by an object or by the boundary between two media
- [sound level](https://dosits.org/glossary/sound-level/) - 10 times the logarithm of the ratio of the mean-square pressure of a sound to the square of a reference sound pressure. Sound pressure level will usually be shortened to sound level on the DOSITS website. Sound pressure level is given in relative units named decibels (dB). Sound pressures for transient signals are sometimes given
- [sound exposure level (SEL)](https://dosits.org/glossary/sound-exposure-level-sel/) - the decibel level of the time integral (summation) of the squared pressure over the duration of a sound event; units of dB re 1 µPa2/s
- [resistance](https://dosits.org/glossary/resistance/) - resistive force is a force whose direction is opposite to the velocity of the body, or of the sum of the other forces; may be referred to as "friction" or "drag".
- [marine fouling](https://dosits.org/glossary/marine-fouling/) - the accumulation of microorganisms, plants, algae, and/or animals on surfaces immersed in the ocean. Buildup on marine vessels poses a significant problem.
- [wake](https://dosits.org/glossary/wake/) - the track of waves left by a ship or other solid object moving through the water. It is caused by the flow of the fluid around the body.
- [source level](https://dosits.org/glossary/source-level/) - the amount of sound radiated by a sound source. It is defined as the intensity of the radiated sound at a distance of 1 meter from the source, where intensity is the amount of sound power transmitted through a unit area in a specified direction. Source level is given as a relative intensity in units
- [oscillation](https://dosits.org/glossary/oscillation/) - a flow periodically changing direction.
- [active acoustics](https://dosits.org/glossary/active-acoustics/) - sound is purposefully generated and received
- [passive margin](https://dosits.org/glossary/passive-margin/) - the transition between oceanic and continental landmasses that is not a plate boundary and therefore experiences little to no volcanic or earthquake activity.
- [subduction zones](https://dosits.org/glossary/subduction-zones/) - places where two tectonic plates move toward each other, and one plate plunges beneath the other plate. Often ocean crust is subducting beneath continental crust
- [backscatter](https://dosits.org/glossary/backscatter/) - the deflection of sound in a scattering process through an angle greater than 90 degrees. Backscatter is the term commonly used to describe the return of sound from the seafloor to the receiver in an active sonar.
- [submarine](https://dosits.org/glossary/submarine/) - underwater
- [methane flux](https://dosits.org/glossary/methane-flux/) - rate of movement of methane from one reservoir to another, between seafloor sediments and the water column.
- [hydrate](https://dosits.org/glossary/hydrate/) - water ice with methane molecules trapped within the ice structure.
- [hydrocarbon](https://dosits.org/glossary/hydrocarbon/) - an organic compound containing only hydrogen and carbon; often occurring in crude oil, natural gas, and coal, as well as plant life.
- [greenhouse gas](https://dosits.org/glossary/greenhouse-gas/) - a gas that traps heat in the atmosphere.
- [Green sea turtle](https://dosits.org/glossary/green-sea-turtle/) - Chelonia mydas
- [dinner bell "effect"](https://dosits.org/glossary/dinner-bell-effect/) - when an underwater sound (or some other stimulant) acts like a dinner bell, alerting and attracting an animal to the presence of a food source.
- [multibeam sonar](https://dosits.org/glossary/multibeam-sonar/) - a sonar system that emits sound waves in a fan shape toward the sea floor and can measure the ocean depth over a wide swath.
- [ensonified](https://dosits.org/glossary/ensonified/) - filled with sound.
- [satellite altimetry](https://dosits.org/glossary/satellite-altimetry/) - satellite radar altimeters measure the ocean surface height (sea level) by measuring the time it takes a radar pulse to make a round-trip from the satellite to the sea surface and back. Features on the sea floor such as mountains add extra pull to Earth's gravity field, drawing more water around them and bulging the
- [yaw](https://dosits.org/glossary/yaw/) - a ship yaw motion is rotation about a vertical axis through the ship or left to right turning of the ship.
- [pitch](https://dosits.org/glossary/pitch-2/) - a ship pitch motion is an up or down, front to back motion.
- [roll](https://dosits.org/glossary/roll-2/) - a ship roll motion in a side-to-side tilting motion.
- [spatial resolution](https://dosits.org/glossary/spatial-resolution/) - the minimum difference or distance between two measured or computed values or objects that can be distinguished. It defines the limit of accuracy for a technique.
- [beamforming](https://dosits.org/glossary/beamforming-2/) - a signal processing technique for the directional transmission or directional reception of a signal.
- [swath](https://dosits.org/glossary/swath/) - an area shaped like a broad strip.
- [zooplankton](https://dosits.org/glossary/zooplankton/) - microscopic animals, such as crustaceans and fish larvae, that drift in the water column.
- [waveform](https://dosits.org/glossary/waveform/) - a waveform presents the sound in a graph as positive and negative pressure on a relative scale (often from -1 to 1) through time. The relative pressure is related to the intensity of the sound.
- [vocal cords](https://dosits.org/glossary/vocal-cords/) - small bands of tissue within the larynx that vibrate (when air passes over them) to produce the sound.
- [tsunami](https://dosits.org/glossary/tsunami/) - a tsunami is a series of ocean waves generated by sudden displacements in the sea floor, landslides, or volcanic activity. In the deep ocean, the tsunami wave may only be a few inches high at the sea surface. When a tsunami wave comes ashore it will increase in height and can become a fast moving
- [seismic wave](https://dosits.org/glossary/seismic-wave/) - a wave of energy caused by the sudden movement of rock, as in an earthquake, or by an explosion. Seismic waves travel trough the Earth and are recorded by a seismometer.
- [shock wave](https://dosits.org/glossary/shock-wave/) - a fully developed compression wave of large amplitude, across which density, pressure, and particle velocity change drastically.
- [Sparker](https://dosits.org/glossary/sparker/) - a sound source that uses an electric spark to generate a broadband signal.
- [risk function](https://dosits.org/glossary/risk-function/) - calculation to predict the probability of a behavioral response based on several factors, including sound received levels
- [rip current](https://dosits.org/glossary/rip-current/) - a strong, narrow surface current that flows rapidly away from the shore, returning the water carried shoreward by waves.
- [repertoire](https://dosits.org/glossary/repertoire/) - suite of behaviors that an animal may use in different contexts; in this case, the number of call types that have been distinguished based on categorization of vocal behavior.
- [rarefaction](https://dosits.org/glossary/rarefaction/) - the instantaneous, local reduction in density of a gas or other medium resulting from passage of a sound wave.
- [Mysticetes](https://dosits.org/glossary/mysticetes/) - these large cetaceans are usually more than 9.1 m (30 ft) long and can be found throughout the ocean. Instead of teeth, mysticetes have a series of horny plates called baleen. The baleen is made from the same materials as human hair and fingernails. The baleen plates hang from the gums of the upper jaw
- [hypothesis](https://dosits.org/glossary/hypothesis/) - a tentative explanation proposed by a scientist for observations that cannot be explained by existing scientific theories. A careful statement of a tentative or provisional conclusion to be tested.
- [harmonic distortion](https://dosits.org/glossary/harmonic-distortion/) - distortion of a pure tone associated with the presence of undesired harmonics at frequencies that are a multiple of the fundamental frequency of the signal.
- [fundamental frequency](https://dosits.org/glossary/fundamental-frequency/) - the lowest frequency in a complex wave.
- [extinction](https://dosits.org/glossary/extinction/) - the end of an organism or group of taxa. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to reproduce and recover may have been lost before this point).
- [expendable bathythermograph](https://dosits.org/glossary/expendable-bathythermograph/) - a probe which is dropped from a ship and measures the temperature as it falls through the water. Two very small wires transmit the temperature data to the ship where it is recorded for later analysis. The probe is designed to fall at a known rate, so that the depth of the probe can be
- [exoskeleton](https://dosits.org/glossary/exoskeleton/) - a hard outer structure, such as the carapace of a lobster or crab, that provides protection or support for an organism (especially invertebrates).
- [endemic](https://dosits.org/glossary/endemic/) - native to or prevalent in a particular area or region; not found in other places.
- [ecotype](https://dosits.org/glossary/ecotype/) - ecologically distinct groups or communities; in this case, groups exhibiting different dietary specializations and corresponding behavioral adaptions, such as hunting techniques and acoustic repertoires.
- [echo-counting](https://dosits.org/glossary/echo-counting/) - when individual (sonar) targets are spaced far enough apart that they can be distinguished from one another, the number of targets are counted (and the number of fish estimated).
- [echo ranging](https://dosits.org/glossary/echo-ranging/) - determining the distance to an object by measuring the time between transmitting a sound signal and hearing its echo.
- [critical angle](https://dosits.org/glossary/critical-angle/) - the arrival angle at which a sound wave traveling from one medium to another medium will be refracted along the interface of the two media. If a wave traveling from one medium to another medium with a higher speed of sound hits the interface between the two media at an arrival angle less than the
- [conductivity-temperature-depth (CTD)](https://dosits.org/glossary/conductivity-temperature-depth-ctd/) - oceanographic tool used to determine the essential physical properties of sea water: conductivity (salinity), temperature, and depth. Depth measurements are derived from measurement of hydrostatic pressure and salinity is measured from electrical conductivity. The CTD may be incorporated into an array of sampling bottles referred to as a carousel" or ""rosette"". The sampling bottles close
- [bathythermograph](https://dosits.org/glossary/bathythermograph/) - an instrument that makes a record of the temperature at various depths in the ocean
- [Chinook salmon](https://dosits.org/glossary/chinook-salmon/) - Oncorhynchus tshawytscha
- [spectrogram](https://dosits.org/glossary/spectrogram/) - a graphic presentation of a sound. A spectrogram plots the frequency vs. time and represents the different intensity of the frequencies with different colors. It is similar to a contour map or bathymetric map where the different colors represent different water depths. Also called a sonogram
- [catadromous](https://dosits.org/glossary/catadromous/) - fish that are born in saltwater, migrate into freshwater as juveniles where they grow into adults, before migrating back into the ocean to spawn.
- [habitat impediment](https://dosits.org/glossary/habitat-impediment/) - a hindrance or obstruction that restricts migratory movements and/or prevents a species from accessing habitat necessary for spawning, foraging, and other activities.
- [Lake sturgeon](https://dosits.org/glossary/lake-sturgeon/) - Acipenser fulvescens
- [moratorium](https://dosits.org/glossary/moratorium-2/) - the suspension (postponement and/or delay) of a particular activity.
- [extant](https://dosits.org/glossary/extant/) - still existing; not extinct.
- [hull](https://dosits.org/glossary/hull/) - the main body of a ship or vessel (most of which goes under the water), including the bottom, sides, and deck but not the masts, superstructure, rigging, engines, and other fittings.
- [ground truth](https://dosits.org/glossary/ground-truth/) - information, or the determination of facts, provided by direct observation. Often performed to check the accuracy of data or other observations.
- [echo-integration](https://dosits.org/glossary/echo-integration/) - when more than one target (e.g. a fish school) is located in an acoustic beam at the same depth, and it is not possible to resolve them separately. The total acoustic energy backscattered by the school or aggregation is integrated together, and this total is divided by the (previously determined) backscattering coefficient of a single
- [scuttle](https://dosits.org/glossary/scuttle/) - to sink (a vessel) deliberately.
- [doppler effect](https://dosits.org/glossary/doppler-effect/) - the raising or lowering of the frequency of a sound due to the motion of the source of the sound relative to the listener. The most common example is the rising frequency of a train whistle as the train approaches.
- [sonobuoy](https://dosits.org/glossary/sonobuoy/) - instrument that is dropped into the ocean (from either an aircraft or ship) to record underwater sounds. It includes a hydrophone and a radio transmitter to send sound signals back to the aircraft or ship. The U.S. Navy uses this instrument to listen for enemy submarines. Sonobuoys may also be used to record marine mammal
- [ice floe](https://dosits.org/glossary/ice-floe/) - a sheet of floating sea ice.
- [pressure ridge](https://dosits.org/glossary/pressure-ridge/) - a ridge produced on floating ice by buckling or crushing under lateral pressure of wind or waves (tide).
- [multiyear ice](https://dosits.org/glossary/multiyear-ice/) - sea ice that has survived at least more than one melting season (i.e. one summer). Multiyear ice contains much less brine and more air pockets than first-year ice. Less brine means "stiffer" ice that is more difficult for icebreakers to navigate and clear.
- [common minke whale](https://dosits.org/glossary/minke-whale/) - Balaenoptera acutorostrata
- [Antarctic minke whale](https://dosits.org/glossary/antarctic-minke-whale/) - Balaenoptera bonaerensis
- [vocalization](https://dosits.org/glossary/vocalizations/) - sounds intentionally produced by animals that may be used for communication, navigation, and feeding. In humans, air is moved from the lungs and across the vocal folds (also known as vocal cords). The vibration of the vocal folds produce sounds that are formed into words and other vocal communication signals. We do not know how
- [standard deviation](https://dosits.org/glossary/standard-deviation/) - an estimate of the variability of a set of measurements about the mean value; it is calculated by computing the square root of the variance.
- [audiogram](https://dosits.org/glossary/audiogram/) - a graph expressing hearing loss (hearing sensitivity) as a function of frequency
- [density](https://dosits.org/glossary/density/) - the distribution of a quantity (such as mass, electricity, or energy) per unit usually of space (such as length, area, or volume); the degree of compactness or concentration of a substance.
- [leopard shark](https://dosits.org/glossary/leopard-shark/) - Triakis semifasciata
- [leopard seal](https://dosits.org/glossary/leopard-seal/) - Hydrurga leptonyx
- [hierarchy](https://dosits.org/glossary/hierarchy/) - a system or organization in which people, animals, or groups are ranked one above the other according to status or authority.
- [walrus](https://dosits.org/glossary/walrus/) - Odobenus rosmarus
- [weddell seal](https://dosits.org/glossary/weddell-seal/) - Leptonychotes weddelli
- [ringed seal](https://dosits.org/glossary/ringed-seal/) - Phoca hispida
- [bearded seal](https://dosits.org/glossary/bearded-seal/) - Erignathus barbatus
- [blue whale](https://dosits.org/glossary/blue-whale/) - Balaenoptera musuculus
- [fin whale](https://dosits.org/glossary/fin-whale/) - Balaenoptera physalus
- [bowhead whale](https://dosits.org/glossary/bowhead-whale/) - Balaena mysticetus
- [cetacean](https://dosits.org/glossary/cetacean/) - order of mammals that includes whales, dolphins and porpoises
- [odontocete](https://dosits.org/glossary/odontocete/) - group of mammals that includes the toothed cetaceans. This includes some whales (such as sperm whales, orca or killer whales, and beaked whales) as well as all dolphins and porpoises.
- [killer whale](https://dosits.org/glossary/killer-whale/) - Orcinus orca
- [sperm whale](https://dosits.org/glossary/sperm-whale/) - Physeter macrocephalus
- [narwhal](https://dosits.org/glossary/narwhal/) - Monodon monoceros
- [Pacific humpback dolphin](https://dosits.org/glossary/pacific-humpback-dolphin/) - also known as the Indo-Pacific humpback dolphin; Sousa chinensis
- [Pacific white-sided dolphin](https://dosits.org/glossary/pacific-white-sided-dolphin/) - Lagenorhynchus obliquidens
- [Atlantic spotted dolphin](https://dosits.org/glossary/atlantic-spotted-dolphin/) - Stenella frontalis
- [kerplunks](https://dosits.org/glossary/kerplunks/) - technique used by dolphins to drive fish away from protected areas such as sea grass beds. A dolphin will lift its tail and lower body out of the water and crash it down on the water surface. This causes a loud splash and creates a trail of bubbles under the water. The bubbles startle the
- [humpback whale](https://dosits.org/glossary/humpback-whale/) - Megaptera novaeangliae
- [Blainville's beaked whale](https://dosits.org/glossary/blainvilles-beaked-whale/) - Mesoplodon densirostris
- [agonistic behavior](https://dosits.org/glossary/agonistic-behavior/) - aggressive or defensive social interaction (such as fighting, fleeing, or submitting) between individuals usually of the same species
- [stridulation](https://dosits.org/glossary/stridulate-stridulation/) - to produce a sound by rubbing two body parts together. Some fish make a shrill creaking noise by rubbing together bodily structures, especially skeletal parts.
- [cavitation](https://dosits.org/glossary/cavitation/) - formation of gas-filled cavities in liquids in motion when the pressure is reduced to a critical value. Low pressure regions are often created by rotating ship propellers. As the propellers rotate, bubbles form in the water. A loud acoustic sound is created when these bubbles collapse.
- [invertebrate](https://dosits.org/glossary/invertebrate/) - an animal that lacks a backbone (marine examples include lobsters, shrimp, squid, clams, crabs, and sea stars).
- [hydrophone array](https://dosits.org/glossary/hydrophone-array/) - several hydrophones attached to each other at known fixed distances so the location of sound sources can be calculated.
- [shadow zone](https://dosits.org/glossary/shadow-zone/) - a region of low sound intensity that sound waves traveling away from a source in the ocean do not reach, usually because the sound waves are refracted away from that region
- [refraction](https://dosits.org/glossary/refraction/) - the bending of a sound wave towards a region of slower sound speed.
- [bedrock](https://dosits.org/glossary/bedrock/) - the hard, solid rock beneath surface materials such as soil as well as sand and other sediments on the ocean floor.
- [medium](https://dosits.org/glossary/medium/) - substance or material that carries or transports the wave from its source to other locations. In the open ocean, the medium through which the wave travels is the ocean water.
- [circumference](https://dosits.org/glossary/circumference/) - the enclosing boundary (perimeter) of a curved geometric figure, especially a circle.
- [latitude](https://dosits.org/glossary/latitude/) - the angular distance of a place north or south of the earth's equator, or of a celestial object north or south of the celestial equator, usually expressed in degrees and minutes.
- [estuary](https://dosits.org/glossary/estuary/) - a coastal body of water formed when freshwater from rivers and streams flows into the ocean, mixing with the seawater. Estuaries and the lands surrounding them are places of transition from land to sea, and from freshwater to saltwater. Although influenced by the tides, estuaries are protected from the full force of ocean waves, winds,
- [peer-reviewed](https://dosits.org/glossary/peer-reviewed/) - scientific papers that have been subjected to evaluation by highly qualified experts in the field, the reviewers are usually anonymous and check the papers for inconsistencies, invalid conclusions and editorial errors
- [peer review](https://dosits.org/glossary/peer-reviewed-2/) - a process by which a scholarly work (such as a paper or a research proposal) is checked by a group of experts in the same field to make sure it meets the necessary standards before it is published or accepted
- [median](https://dosits.org/glossary/median/) - the "middle" value in the list of numbers. To find the median, observations are arranged in order from smallest to largest value. If there is an odd number of observations, the median is the middle value. If there is an even number of observations, the median is the average of the two middle values.
- [root-mean-square pressure](https://dosits.org/glossary/root-mean-square-pressure/) - the square root of the average of the square of the pressure of the sound signal over a given duration. Root-mean-square is often abbreviated rms
- [pH](https://dosits.org/glossary/ph/) - a figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid, and higher values more alkaline (basic).
- [auditory brainstem response (ABR)](https://dosits.org/glossary/auditory-brainstem-response-abr/) - Whenever a sound wave is detected by the ear, it triggers a number of neuro-physiological responses along the auditory pathway. An auditory brainstem response test is an objective test that measures the electrical potential produced in response to sound stimuli by the synchronous discharge of the first through sixth order neurons in the auditory nerve
- [phocids or true seals](https://dosits.org/glossary/phocids-or-true-seals/) - seals, such as harbor seals, that have no visible ear flap. They have a streamlined body with short front flippers. Their hind flippers are directed backward and they are not used for walking on land.
- [harbor seal](https://dosits.org/glossary/harbor-seal/) - Phoca vitulina
- [polar bear](https://dosits.org/glossary/polar-bear/) - Ursus maritimus
- [North Atlantic right whale](https://dosits.org/glossary/north-atlantic-right-whale/) - Eubalaena glacialis
- [bottlenose dolphin](https://dosits.org/glossary/bottlenose-dolphin/) - Tursiops truncatus
- [white-beaked dolphin](https://dosits.org/glossary/white-beaked-dolphin/) - Lagenorhynchus albirostris
- [pinniped](https://dosits.org/glossary/pinniped/) - group of mammals that includes seals, sea lions and walruses
- [harbor porpoise](https://dosits.org/glossary/harbor-porpoise/) - Phocoena phocoena
- [beluga whale](https://dosits.org/glossary/beluga-whale/) - Delphinapterus leucas
- [receiver](https://dosits.org/glossary/receiver/) - something that listens for or receives sound; it may or may not record the sound
- [startle response](https://dosits.org/glossary/startle-response/) - a largely involuntary, defensive response to a sudden and/or threatening stimuli, such as a flash of light, a sudden movement, or loud noise. In fishes, this behavior is often displayed as a sudden bending of the body, and is a characteristic escape response.
- [smolt](https://dosits.org/glossary/smolt/) - a young salmon (or trout) at the stage of development when it assumes the silvery color of the adult and is ready to migrate to the sea.
- [moratorium](https://dosits.org/glossary/moratorium/) - a temporary prohibition of an activity.
- [anadromous](https://dosits.org/glossary/anadromous/) - fish that are born in fresh water, migrate to the ocean to grow into adults, and return to fresh water to spawn.
- [hydrokinetic](https://dosits.org/glossary/hydrokinetic/) - the conversion of kinetic energy produced by flowing water into electricity, or other forms of energy.
- [diadromous](https://dosits.org/glossary/diadromous/) - migrating between saltwater and freshwater to complete a life cycle.
- [High Arctic](https://dosits.org/glossary/high-arctic/) - the northernmost part of the Arctic, including the circumpolar Arctic Ocean with its surface ice and its most northerly coastal margins and islands.
- [sub-arctic](https://dosits.org/glossary/subarctic/) - relating to the region immediately south of the Arctic Circle.
- [click](https://dosits.org/glossary/click/) - a short pulse of sound, often used to describe pulses produced by toothed whales for echolocation.
- [seismometer](https://dosits.org/glossary/seismometer/) - an instrument that records ground movement; used to detect and measure earthquakes
- [waveguide](https://dosits.org/glossary/waveguide/) - a structure that guides waves by restricting the wave movement in one or more dimensions resulting in efficient transmission of the wave. For example, the SOFAR channel is a waveguide in the ocean.
- [front](https://dosits.org/glossary/front/) - a boundary between two water masses with differing properties such as temperature and salinity
- [eddy](https://dosits.org/glossary/eddy/) - energetic, swirling, unsteady flows that are found almost everywhere in the ocean
- [exclusive economic zone](https://dosits.org/glossary/18090/) - a zone extending up to 200 nautical miles (370km) from a nation's territorial waters into the ocean where that nation has jurisdiction over natural resources such as fisheries and energy production. The Exclusive Economic Zone is defined in the United Nations Convention on the Law of the Sea. Also called the EEZ.
- [continental shelf](https://dosits.org/glossary/continental-shelf/) - the gently sloping undersea region between a continent and the deep ocean.
- [heavy oil](https://dosits.org/glossary/heavy-oil/) - very thick oil that has little to no evaporation and/or dissolution properties and weathers very slowly. Heavy oil is depleted in hydrogen relative to light oil, and fewer refined products are derived from heavy oil. Cleanup of heavy oils is also very difficult. Heavy crude oil is an example of a heavy oil.
- [light oil](https://dosits.org/glossary/light-oil/) - very fluid oil that has a strong odor, high concentrations of soluble, toxic compounds, and a high evaporation rate. Light oils consist largely of benzene and toluene. Gasoline and diesel fuel are examples of light oils.
- [effective source level](https://dosits.org/glossary/effective-source-level/) - the source level of an array when considered as a single omnidirectional sound source
- [far field](https://dosits.org/glossary/far-field/) - the sound field at a distance from a sound source array where the wave fronts created by the individual sound sources are in phase
- [near field](https://dosits.org/glossary/near-field/) - the sound field near a sound source array where complex constructive and destructive interference occurs among the wave fronts created by the individual sound sources
- [source array](https://dosits.org/glossary/source-array/) - multiple sound sources combined to operate together for a specific purpose
- [Cycle](https://dosits.org/glossary/cycle/) - one complete vibration of a particle through a wave, e.g., from equilibrium to the crest through equilibrium to the trough and back to equilibrium.
- [Period](https://dosits.org/glossary/period/) - the time duration between any point on a wave and the same point on the next wave, e.g., from one wave crest to the next wave crest; the time for a particle to make one complete cycle at a given point
- [Northern fur seal](https://dosits.org/glossary/northern-fur-seal/) - Callorhinus ursinus
- [thick-billed murre](https://dosits.org/glossary/thick-billed-murre/) - Uria lomvia
- [black-legged kittiwake](https://dosits.org/glossary/black-legged-kittiwake/) - Rissa tridactyla
- [submarine canyon](https://dosits.org/glossary/submarine-canyon/) - narrow, steep-sided valleys on the seafloor.
- [threatened](https://dosits.org/glossary/threatened/) - any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range (as defined in the U.S. Endangered Species Act).
- [krill](https://dosits.org/glossary/krill/) - small, shrimp-like invertebrates (also called euphausiids) that swarm in dense patches within the water column or at the sea surface. They have hard mouths and tail parts that reflect sound. Krill is an important food source for many marine organisms including whales and seals.
- [keystone](https://dosits.org/glossary/keystone/) - a species on which other species in an ecosystem largely depend, such that if it were removed, the ecosystem would drastically change
- [biodiversity](https://dosits.org/glossary/biodiversity/) - a contraction of “biological diversity,” it generally refers to the amount of variability within species, among species, and among ecosystems.
- [propagation](https://dosits.org/glossary/propagation/) - the movement of sound through a medium.
- [perceive](https://dosits.org/glossary/perceive/) - to recognize, discern, or understand.
- [phase](https://dosits.org/glossary/phase/) - the location of a point within a wave cycle of a repetitive waveform, measured as the fraction of a wave cycle and often expressed as an angle; one cycle is 360º or 2 π radians.
- [Hydrothermal](https://dosits.org/glossary/hydrothermal-2/) - relating to hot water circulation in the ocean crust.
- [Mid-ocean ridge](https://dosits.org/glossary/mid-ocean-ridge-2/) - underwater mountain chain where new ocean crust is created.
- [Epicenter](https://dosits.org/glossary/epicenter-2/) - the surface location of an earthquake.
- [pack ice](https://dosits.org/glossary/pack-ice-2/) - a large area of floating ice pieces that have been driven together by wind, currents, etc. to form a nearly continuous mass of ice
- [austral](https://dosits.org/glossary/austral/) - southern hemisphere
- [circumpolar](https://dosits.org/glossary/circumpolar/) - located around or found in one of Earth's polar regions
- [steps](https://dosits.org/glossary/steps/) - a break or irregular change in frequency of a whistle.
- [ocean acidification](https://dosits.org/glossary/ocean-acidification/) - a reduction in the pH of the ocean over an extended period of time, caused primarily by uptake of carbon dioxide (CO2) from the atmosphere. When CO2 is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed "ocean acidification"
- [acoustic index](https://dosits.org/glossary/acoustic-index/) - a statistic that summarizes several aspects of the distribution of acoustic energy and information. Acoustic indices have been developed to estimate characteristics of the acoustic production of biological communities including richness and heterogeneity.
- [acoustic signature](https://dosits.org/glossary/acoustic-signature/) - acoustic characteristics or attributes of a sound source that can be used for its identification.
- [metamorphosis](https://dosits.org/glossary/metamorphosis/) - the process of transformation from an immature form to an adult form.
- [acoustic environment](https://dosits.org/glossary/acoustic-environment/) - the composite of all sounds in an environment. The perception of the acoustic environment for each animal will vary depending on its hearing abilities.
- [cochlea](https://dosits.org/glossary/cochlea/) - the spiral-shaped chamber within the inner ear that transforms sound waves into nerve impulses. The cochlea is a fluid-filled organ that houses many structures related to hearing, including the basilar membrane and the organ of Corti. It is considered the organ of hearing.
- [adaptation](https://dosits.org/glossary/adaptation/) - an alteration in the structure or function of an organism or any of its parts that results in the organism becoming better fitted to survive and multiply in its environment.
- [frequency weighting](https://dosits.org/glossary/frequency-weighting/) - a method for quantitatively compensating for the fact the animals do not hear equally well at all frequencies within their hearing range.
- [phon](https://dosits.org/glossary/phon/) - a unit of loudness for pure tones that accounts for the perceived loudness of tones; the number of phon of a sound is the decibel of a sound at 1 kHz that is perceived to be just as loud.
- [C-weighting](https://dosits.org/glossary/c-weighting/) - a frequency weighting function that was originally designed to predict the human ear’s sensitivity to tones at high noise levels; however, nearly all noise measurements for hearing conservation are measured with A-weighting; units dB(C) or dBC.
- [essential fish habitat (EFH)](https://dosits.org/glossary/essential-fish-habitat-efh/) - those waters and substrate necessary for fish for spawning, feeding, or growth to maturity.
- [ocean observatory](https://dosits.org/glossary/ocean-observatory/) - a networked array of sensor systems that measure the physical, chemical, geological and biological variables in the ocean and seafloor as well as the overlying atmosphere.
- [red drum](https://dosits.org/glossary/red-drum/) - Sciaenops ocellatus
- [hydraulic hammer](https://dosits.org/glossary/hydraulic-hammer/) - a large, industrial hammer that is operated by a fluid that is under pressure (hydraulics). A hydraulic hammer is a modern type of piling hammer used in place of diesel and air hammers for driving steel pipe, precast concrete, and timber piles.
- [equal energy hypothesis](https://dosits.org/glossary/equal-energy-hypothesis/) - assumption that sounds of equal SELcum produce an equal risk for hearing loss (i.e., if the SELcum of two sources are similar, a sound from a lower level source with a longer exposure duration may have similar risks to a shorter duration exposure from a higher level source).
- [symbiotic](https://dosits.org/glossary/symbiotic/) - having an interdependent relationship that benefits both parties involved.
- [epicenter](https://dosits.org/glossary/epicenter/) - the point on the earth's surface (on land or underwater) vertically above the focus of an earthquake.
- [Tertiary wave](https://dosits.org/glossary/tertiary-wave/) - seismic energy that has been converted into acoustic energy in the ocean. Also known as a T-wave"."""
- [mid-ocean ridge](https://dosits.org/glossary/mid-ocean-ridge/) - underwater mountain chain where new ocean crust is created.
- [hydrothermal](https://dosits.org/glossary/hydrothermal/) - relating to hot water circulation in the ocean crust.
- [hearing groups](https://dosits.org/glossary/hearing-groups/) - groups of marine mammals defined by the generalized range of frequencies that species in the group can hear.
- [auditory weighting function](https://dosits.org/glossary/auditory-weighting-function/) - a mathematical equation that compensates for the fact that animals do not hear equally well at all frequencies.
- [acoustic threshold](https://dosits.org/glossary/acoustic-threshold/) - the received level at which an effect from acoustic exposure may begin to occur.
- [equal latency](https://dosits.org/glossary/equal-latency/) - the assumption in hearing studies that sounds that are perceived to be equally loud result in equal response times, thereby allowing response time to be a proxy for perceived loudness.
- [stewardship](https://dosits.org/glossary/stewardship/) - the conducting, supervising, or managing of something, especially, the careful and responsible management of something entrusted to one's care.
- [transponder](https://dosits.org/glossary/transponder/) - a device for receiving an acoustic signal and automatically transmitting a unique return signal in response. Transponders are often used to show the location of something.
- [whistles](https://dosits.org/glossary/whistles/) - narrow-band, tonal sounds produced by many toothed whales for communication purposes. Whistles are frequency-modulated, which means the pitch of the sound changes over time.
- [vocal learning](https://dosits.org/glossary/vocal-learning/) - the modification of an animal’s vocalization(s) based on acoustic signals in its environment, such as vocalizations by conspecifics.
- [stereotyped](https://dosits.org/glossary/stereotyped/) - fixed or settled in form.
- [oral cavity](https://dosits.org/glossary/oral-cavity/) - the mouth, which forms the first chamber of the digestive system. It includes the space surrounded by the lips, teeth, hard and soft palates, cheeks, and tongue. The oral cavity ends at border of the pharynx, which is approximately the line just anterior to the tonsils.
- [buccal cavity](https://dosits.org/glossary/buccal-cavity/) - the anterior portion of the oral cavity, also sometimes referred to as the vestibule or entry area of the oral cavity. It is the region bounded by teeth and gums, jaws, and cheeks.
- [fluke](https://dosits.org/glossary/fluke/) - the two lobes of a whale tail.
- [homologous](https://dosits.org/glossary/homologous/) - similar in position, structure, and evolutionary origin but not necessarily in function.
- [laryngeal sac](https://dosits.org/glossary/laryngeal-sac/) - an inflatable “pouch”, or often a pair of pouches, that are generally located ventral to the larynx in many mammals, particularly in primates (but not in humans), hooved mammals (e.g., reindeer, horses, antelopes), and cetaceans. The functions of laryngeal sacs are not completely understood. Like the vocal sacs of frogs, laryngeal sacs may amplify calls
- [narial passages](https://dosits.org/glossary/narial-passages/) - the air spaces that connect the throat region with the openings of the nose, known as the nares. It is also sometimes referred to as the nasal passages.
- [lunge-feeding](https://dosits.org/glossary/lunge-feeding/) - a method of feeding underwater in which the predator moves forward with its mouth open, engulfing the prey along with the water surrounding it.
- [ping](https://dosits.org/glossary/ping/) - to query (another computer on a network, or in this case, an acoustic transponder) to determine the location of it.
- [tiger shark](https://dosits.org/glossary/tiger-shark/) - Galeocerdo cuvier
- [blue shark](https://dosits.org/glossary/blue-shark/) - Prionace glauca
- [basking shark](https://dosits.org/glossary/basking-shark/) - Cetorhinus maximus
- [Atlantic salmon](https://dosits.org/glossary/atlantic-salmon/) - Salmo salar
- [great white shark](https://dosits.org/glossary/great-white-shark/) - Carcharodon carcharias
- [natal](https://dosits.org/glossary/natal/) - grown, produced, or originating in a particular place or in the vicinity (of, relating to, or present at birth).
- [Cape fur seal](https://dosits.org/glossary/cape-fur-seal/) - Arctocephalus pusillus
- [elasmobranch](https://dosits.org/glossary/elasmobranch/) - a group of cartilaginous fish that comprises the sharks, rays, and skates.
- [bel](https://dosits.org/glossary/bel/) - a unit used in the comparison of power levels or of intensities of sounds corresponding to an intensity ratio of 10:1.
- [pulse](https://dosits.org/glossary/pulse/) - a short duration broadband signal.
- [red grouper](https://dosits.org/glossary/red-grouper/) - Epinephelus morio
- [vulnerable](https://dosits.org/glossary/vulnerable/) - susceptible to being hurt or damaged.
- [critical habitat](https://dosits.org/glossary/critical-habitat/) - specific geographic area(s) that contains features essential for the conservation of a threatened or endangered species and that may require special management and protection.
- [pitch](https://dosits.org/glossary/pitch/) - an up-or-down movement of the front (bow) of a vessel (ship, glider, etc.).
- [roll](https://dosits.org/glossary/roll/) - the rotation of a vessel about its longitudinal (front/back) axis.
- [pollack](https://dosits.org/glossary/pollack/) - Pollachius pollachius
- [saithe](https://dosits.org/glossary/saithe/) - Pollachius virens
- [diurnal](https://dosits.org/glossary/diurnal/) - of or during the day.
- [pelagic](https://dosits.org/glossary/pelagic/) - of, relating to, or living or occurring in the open ocean.
- [sprat](https://dosits.org/glossary/sprat/) - Sprattus sprattus
- [Atlantic mackerel](https://dosits.org/glossary/atlantic-mackerel/) - Scomber scombrus
- [European sea bass](https://dosits.org/glossary/european-sea-bass/) - Dicentrarchus labrax
- [white noise](https://dosits.org/glossary/white-noise/) - a heterogeneous mixture of sound waves extending over a wide frequency range (but equal intensities).
- [immunological response](https://dosits.org/glossary/immunological-response/) - a bodily defense reaction that recognizes an invading substance (such as a virus, fungus, or bacteria, or a transplanted organ) and produces antibodies specific to that invading substance.
- [communication space](https://dosits.org/glossary/communication-space/) - the area over which one individual can detect the signal of another.
- [conspecific](https://dosits.org/glossary/conspecific/) - animals (or plants) belonging to the same species
- [extirpation](https://dosits.org/glossary/extirpation/) - the movement of an entire population out of a region
- [grey seal](https://dosits.org/glossary/grey-seal/) - Halichoerus grypus
- [fat emboli](https://dosits.org/glossary/fat-emboli/) - a fat globule in the bloodstream that is often caused by physical trauma such as fracture of long bones, soft tissue traum, or burns.
- [sea state](https://dosits.org/glossary/sea-state/) - condition of the surface of the ocean, measured on a scale 0-9, categorized by wave height.
- [kinetic energy](https://dosits.org/glossary/kinetic-energy/) - the energy possessed by a system or object as a result of its motion.
- [peak pressure](https://dosits.org/glossary/peak-pressure/) - the range in pressure between zero and the greatest pressure of the signal.
- [dB peak](https://dosits.org/glossary/db-peak/) - a unit of relative pressure when the pressure of the sound wave is characterized as the peak pressure.
- [dB peak-peak](https://dosits.org/glossary/db-peak-peak/) - a unit of relative pressure when the pressure of the sound wave is characterized as the peak-to-peak pressure.
- [hydrostatic pressure](https://dosits.org/glossary/hydrostatic-pressure/) - The pressure at a point in a fluid at rest due to the weight of the fluid above it.
- [overpressure](https://dosits.org/glossary/overpressure/) - The pressure in the shock wave from an explosion that exceeds the existing atmospheric or hydrostatic pressure in the medium through which the shock wave is propagating.
- [sonoluminescence](https://dosits.org/glossary/sonoluminescence/) - the production of light as a result of the passing of sound waves through a liquid medium. The sound waves cause the formation of bubbles that emit bright flashes of light when they collapse.
- [detection threshold](https://dosits.org/glossary/detection-threshold/) - the signal-to-noise ratio (SNR) (in decibels) required to achieve a specified probability of detection p(D) for a given probability of false alarm p(FA) when deciding whether or not a signal is present at a receiver.
- [signal excess](https://dosits.org/glossary/signal-excess/) - the amount (in decibels) by which the signal- to-noise ratio (SNR) exceeds the detection threshold (DT).
- [miss](https://dosits.org/glossary/miss/) - Incorrectly deciding on the basis of a statistical test that a signal is absent when it is in fact present. A false negative.
- [detection probability p(D)](https://dosits.org/glossary/detection-probability-pd/) - the probability of correctly deciding on the basis of a statistical test that a signal is present when it is in fact present.
- [false alarm probability p(FA)](https://dosits.org/glossary/false-alarm-probability-pfa/) - the probability of incorrectly deciding on the basis of a statistical test that a signal is present when it is in fact absent.
- [null decision](https://dosits.org/glossary/null-decision/) - correctly deciding on the basis of a statistical test that a signal is absent when it is in fact absent.
- [explosive sound source](https://dosits.org/glossary/explosive-sound-source/) - a device that uses explosive material to generate controlled acoustic energy.
- [SUS (Signal, Underwater Sound)](https://dosits.org/glossary/sus-signal-underwater-sound/) - an explosive sound source used by the U.S. Navy that consists of 0.82-kg (1.8-lb) of TNT explosive material.
- [pneumatic](https://dosits.org/glossary/pneumatic/) - containing or operated by air or gas under pressure.
- [TNT](https://dosits.org/glossary/tnt/) - trinitrotoluene; a chemical compound used as an explosive material.
- [bubble pulses](https://dosits.org/glossary/bubble-pulses/) - secondary shock waves of explosions in which the bubbles repeatedly grow larger and smaller.
- [bubble frequency](https://dosits.org/glossary/bubble-frequency/) - the frequency equal to the reciprocal of the time interval between the shock wave and the first bubble pulse.
- [transmission loss](https://dosits.org/glossary/transmission-loss/) - the decrease in acoustic intensity (due to spreading and/or attenuation) as an underwater sound wave propagates outwards from a source.
- [target strength](https://dosits.org/glossary/target-strength/) - the amount of sound reflected back toward a sonar by a target.
- [receiver-operating-characteristic (ROC) curve](https://dosits.org/glossary/receiver-operating-characteristic-roc-curve/) - a curve that plots the cumulative distribution functions of the false-alarm probability and the detection probability on the x-axis and y-axis, respectively, to select the optimal detection threshold.
- [false alarm](https://dosits.org/glossary/false-alarm/) - incorrectly deciding on the basis of a statistical test that a signal is present when it is in fact absent. A false positive.
- [mitigate](https://dosits.org/glossary/mitigate/) - to make (something) less severe or harmful.
- [acoustic impedance](https://dosits.org/glossary/acoustic-impedance/) - the amount of sound pressure generated by a given vibration at a specific frequency.
- [characteristic impedance](https://dosits.org/glossary/characteristic-impedance/) - a material property of a medium, defined as the density of the medium times the sound speed through the medium.
- [North Pacific right whale](https://dosits.org/glossary/north-pacific-right-whale/) - Eubalaena japonica
- [carapace](https://dosits.org/glossary/carapace/) - A hard, protective, shell-like outer covering found in crustaceans (e.g. crabs and lobsters) as well as turtles.
- [Spiny Lobster](https://dosits.org/glossary/spiny-lobster/) - Palinurus elephas
- [Yangtze finless porpoise](https://dosits.org/glossary/yangtze-finless-porpoise/) - Neophocaena phocaenoides
- [Franciscana dolphin](https://dosits.org/glossary/franciscana-dolphin/) - Pontoporia blainvillei
- [striped dolphin](https://dosits.org/glossary/striped-dolphin/) - Stenella coeruleoalba
- [beamforming](https://dosits.org/glossary/beamforming/) - a general signal processing technique used to control the directionality of the reception or transmission of a signal on an array of sensors. Using beamforming during sound transmission, the majority of signal energy is transmitted in a specified direction. During sound reception, beamforming allows sensors to predominantly receive energy from a specified direction
- [caudal peduncle](https://dosits.org/glossary/caudal-peduncle/) - The narrow part of the body to which the caudal fin (or tail) attaches to the body.
- [knots](https://dosits.org/glossary/knots/) - a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph.
- [semi-terrestrial](https://dosits.org/glossary/semi-terrestrial/) - living mostly on land but requiring water and/or a moist environment (esp. as a breeding site). Most amphibians (e.g. frogs) and many crustaceans (e.g. crabs) are semi-terrestrial.
- [setae](https://dosits.org/glossary/setae/) - a stiff hair, bristle, or bristle like part on an organism.
- [dorsal](https://dosits.org/glossary/dorsal/) - of or pertaining to the upper surface.
- [ventral](https://dosits.org/glossary/ventral/) - of, pertaining to, or situated at the back or upper side.
- [Kina](https://dosits.org/glossary/kina/) - Evechinus chloroticus
- [American lobster](https://dosits.org/glossary/american-lobster/) - Homarus americanus
- [California mantis shrimp](https://dosits.org/glossary/california-mantis-shrimp/) - Hemisquilla californiensis
- [Australian freshwater crayfish](https://dosits.org/glossary/australian-freshwater-crayfish/) - Cherax destructor
- [oval squid](https://dosits.org/glossary/oval-squid/) - Sepiotheutis lessoniana
- [common octopus](https://dosits.org/glossary/common-octopus/) - Octopus vulgaris
- [common prawn](https://dosits.org/glossary/common-prawn/) - Palaemon serratus
- [central nervous system](https://dosits.org/glossary/central-nervous-system/) - the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.
- [Barth’s myochordotonal organs (Barth’s MCO)](https://dosits.org/glossary/barths-myochordotonal-organs-barths-mco/) - thin-walled sensory organ found in the exoskeleton on each leg of semi-terrestrial ocypodid crabs.
- [echinoderm](https://dosits.org/glossary/echinoderm/) - marine invertebrates with tube feet and five-part radially symmetrical bodies. The group includes sea urchins, sea stars, sea cucumbers, brittle stars, and crinoids.
- [trachea](https://dosits.org/glossary/trachea/) - a large membranous tube reinforced by rings of cartilage, extending from the larynx to the bronchial tubes and conveying air to and from the lungs; the windpipe.
- [Comprehensive Nuclear-Test-Ban Treaty](https://dosits.org/glossary/comprehensive-nuclear-test-ban-treaty/) - The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosions on Earth whether for military or for peaceful purposes. It was adopted by the United NAtions General Assembly in 1996. The treaty contains provisions for monitoring which include acoustic monitoring. The treaty is not yet in force because it has not been ratified by some nations.
- [sound intensity level](https://dosits.org/glossary/sound-intensity-level/) - 10 times the logarithm of the ratio of the intensity of a sound wave to a reference intensity; also known as intensity.
- [Dugong](https://dosits.org/glossary/dugong/) - Dugong dugon
- [sea otter](https://dosits.org/glossary/sea-otter/) - Enhydra lutris
- [pink snapper](https://dosits.org/glossary/pink-snapper/) - Pagrus auratus
- [toadfish](https://dosits.org/glossary/toadfish/) - opsanus tau
- [calve](https://dosits.org/glossary/calve/) - the sudden release and breaking away of a mass of ice from a glacier, iceberg, ice front, or ice shelf.
- [particle motion](https://dosits.org/glossary/particle-motion/) - the change in position of a particle with respect to time; in acoustics, particle motion is vibratory motion in which the particles move back and forth around an equilibrium point.
- [displacement](https://dosits.org/glossary/displacement/) - the linear distance in a given direction between a point and a reference position.
- [acceleration](https://dosits.org/glossary/acceleration/) - the rate of change of velocity with respect to magnitude or direction.
- [plane wave](https://dosits.org/glossary/plane-wave/) - a wave in which the wave fronts are a series of parallel planes.
- [decapod crustacean](https://dosits.org/glossary/decapod-crustacean/) - crustacean that has five pairs of walking legs, a segmented body, and chitinous exoskeleton. Examples include lobsters, crayfish, crabs, shrimps, and prawns.
- [algorithm](https://dosits.org/glossary/algorithm/) - a step-by-step procedure for calculations/solving a problem.
- [auditory bulla](https://dosits.org/glossary/auditory-bulla/) - a hollow, bony structure that encloses parts of the middle and inner ear.
- [benthic](https://dosits.org/glossary/benthic/) - living on the bottom of the sea (or a lake).
- [fathead minnow](https://dosits.org/glossary/fathead-minnow/) - Pimephales promelas
- [derived](https://dosits.org/glossary/derived/) - formed or developed from something else; not original. NOTE: different areas of science have more specialized definitions for this term (e.g. in paleontology, derived characteristics means something has evolved to fit a particular pressure).
- [mandible](https://dosits.org/glossary/mandible/) - one of the jaw structures of animals. For example, in vertebrates, it is the lower jaw bone; in insects it is one of the anterior mouth parts.
- [stereociliary bundles](https://dosits.org/glossary/stereociliary-bundles/) - groups of hair-like projections on the upper surface of a hair cell. When stereocila bend, they trigger a release of chemicals that initiates the electrical signal (neural impulse) that is carried to and processed by the brain.
- [cardioid](https://dosits.org/glossary/cardioid/) - a heart-shaped curve generated by a point on a circle that rolls without slipping on another fixed circle of the same diameter.
- [beam pattern](https://dosits.org/glossary/beam-pattern/) - a graphical or other description of the response of a transducer used for sound transmission or reception as a function of the direction of the transmitted or incident sound waves.
- [vector](https://dosits.org/glossary/vector/) - a quantity, such as a velocity or force, that has both magnitude and direction.
- [elephant seal](https://dosits.org/glossary/elephant-seal/) - Mirounga
- [little skate](https://dosits.org/glossary/little-skate/) - Raja erinacea
- [southern right whale](https://dosits.org/glossary/southern-right-whale/) - Eubalaena australis
- [Amazon river dolphin](https://dosits.org/glossary/amazon-river-dolphin/) - Inia geoffrensis
- [Baiji](https://dosits.org/glossary/baiji/) - Lipotes vexillifer
- [common dolphin](https://dosits.org/glossary/common-dolphin/) - Delphinus capensis (long-beaked common dolphin), Delphinus delphis (short-beaked common dolphin)
- [false killer whale](https://dosits.org/glossary/false-killer-whale/) - Pseudorca crassidens
- [finless porpoise](https://dosits.org/glossary/finless-porpoise/) - Neophocaena phocaenoides
- [Northern bottlenose whale](https://dosits.org/glossary/northern-bottlenose-whale/) - Hyperoodon ampullatus
- [pilot whale](https://dosits.org/glossary/pilot-whale/) - Globicephala spp.
- [Risso's dolphin](https://dosits.org/glossary/rissos-dolphin/) - Grampus griseus
- [spinner dolphin](https://dosits.org/glossary/spinner-dolphin/) - Stenella longirostris
- [white-sided dolphin](https://dosits.org/glossary/white-sided-dolphin/) - Lagenorhynchus spp.
- [vaquita](https://dosits.org/glossary/vaquita/) - Phocoena sinus
- [California sea lion](https://dosits.org/glossary/california-sea-lion/) - Zalophus californianus
- [hawaiian monk seal](https://dosits.org/glossary/hawaiian-monk-seal/) - Monachus schauinslandi
- [Northern elephant seal](https://dosits.org/glossary/northern-elephant-seal/) - Mirounga angustirostris
- [physiological stress](https://dosits.org/glossary/physiological-stress/) - a reaction to a change that requires a physical, mental or emotional adjustment or response.
- [stress response](https://dosits.org/glossary/stress-response/) - the natural coping mechanism that allows the body to deal with stressful events. A group of physiological and behavioral processes enable an animal to adapt to changes in their environment.
- [ototoxic](https://dosits.org/glossary/ototoxic/) - causing damage to the ear or its nerve supply.
- [auditory system](https://dosits.org/glossary/auditory-system/) - the sensory system for hearing, consisting of the ear and the central nervous system.
- [electro-physiological response](https://dosits.org/glossary/electro-physiological-response/) - the electrical activity of neurons when stimulated (see auditory brainstem response (ABR)).
- [wave front](https://dosits.org/glossary/wave-front/) - a surface consisting of all points on a wave at the same position in a wave cycle.
- [prehensile](https://dosits.org/glossary/prehensile/) - adapted for seizing, grasping, or holding, especially by wrapping around an object.
- [Caribbean spiny lobster](https://dosits.org/glossary/caribbean-spiny-lobster/) - Panulirus argus
- [cleaner shrimp](https://dosits.org/glossary/cleaner-shrimp/) - Periclimenes longicarpus
- [Northern shrimp](https://dosits.org/glossary/northern-shrimp/) - Pandalus borealis
- [European spiny lobster](https://dosits.org/glossary/european-spiny-lobster/) - Palinurus elephas
- [Long-spined sea urchin](https://dosits.org/glossary/long-spined-sea-urchin/) - Diadema setosum
- [mudflat fiddler crab](https://dosits.org/glossary/mudflat-fiddler-crab/) - Uca rapax
- [new england mussel](https://dosits.org/glossary/new-england-mussel/) - Mytilus edilus
- [snapping shrimp](https://dosits.org/glossary/snapping-shrimp/) - Alpheus heterochaelis
- [sand fiddler crab](https://dosits.org/glossary/sand-fiddler-crab/) - Uca pugilator
- [American shad](https://dosits.org/glossary/american-shad/) - Alosa sapidissima
- [Atlantic croaker](https://dosits.org/glossary/atlantic-croaker/) - Micropogonias undulatus
- [black drum](https://dosits.org/glossary/black-drum/) - Pogonias cromis
- [black rockfish](https://dosits.org/glossary/black-rockfish/) - Sebastes melanops
- [blue-fin tuna](https://dosits.org/glossary/blue-fin-tuna/) - Thunnus thynnus
- [blue rockfish](https://dosits.org/glossary/blue-rockfish/) - Sebastes mystinus
- [blue whiting](https://dosits.org/glossary/blue-whiting/) - Micromesistius poutassou
- [cod](https://dosits.org/glossary/cod/) - Gadus morhua
- [common carp](https://dosits.org/glossary/common-carp/) - Cyprinus carpio carpio
- [European perch](https://dosits.org/glossary/european-perch/) - Perca fluviatilis
- [goldfish](https://dosits.org/glossary/goldfish/) - Carassius auratus auratus
- [goliath grouper](https://dosits.org/glossary/goliath-grouper/) - Epinephelus itajara
- [gray triggerfish](https://dosits.org/glossary/gray-triggerfish/) - Balistes capriscu
- [gudgeon](https://dosits.org/glossary/gudgeon/) - Gobio gobio
- [haddock](https://dosits.org/glossary/haddock/) - Melanogrammus aeglefinus
- [kelp rockfish](https://dosits.org/glossary/kelp-rockfish/) - Sebastes atrovirens
- [ladyfish](https://dosits.org/glossary/ladyfish/) - Elops saurus
- [Lusitanian toadfish](https://dosits.org/glossary/lusitanian-toadfish/) - Halobatrachus didactylus
- [Northern seahorse](https://dosits.org/glossary/northern-seahorse/) - Hippocampus erectus
- [oscar](https://dosits.org/glossary/oscar/) - Astronotus ocellatus
- [oyster toadfish](https://dosits.org/glossary/oyster-toadfish/) - Opsanus tau
- [pink snappers](https://dosits.org/glossary/pink-snappers/) - Pagrus auratus
- [queen parrotfish](https://dosits.org/glossary/queen-parrotfish/) - Scarus vetula
- [rainbow trout](https://dosits.org/glossary/rainbow-trout/) - Oncorhynchus mykiss
- [sablefish](https://dosits.org/glossary/sablefish/) - Anoplopoma fimbria
- [silver perch](https://dosits.org/glossary/silver-perch/) - Bairdiella chrysoura
- [streaked gurnards](https://dosits.org/glossary/streaked-gurnards/) - Trigloporus lastoviza
- [stripers](https://dosits.org/glossary/stripers/) - Morone saxatilis
- [yellowtail rockfish](https://dosits.org/glossary/yellowtail-rockfish/) - Sebastes flavidus
- [plainfin midshipman](https://dosits.org/glossary/plainfin-midshipman/) - Porichthys notatus
- [precision](https://dosits.org/glossary/precision/) - the degree to which repeated measurements under unchanged conditions show the same results; reproducibility; repeatability.
- [histogram](https://dosits.org/glossary/histogram/) - a representation of a distribution by means of rectangles whose widths represent class intervals and whose areas are proportional to the corresponding frequencies of occurrence.
- [distribution](https://dosits.org/glossary/distribution/) - the frequency of occurrence of a specific value in a set of measurements.
- [entanglement](https://dosits.org/glossary/entanglement/) - whales, seals, sea lions, and other marine animals may come into contact with lost or active fishing gear, causing the gear to become twisted around their bodies and/or snagged on different body parts. When this occurs, the animal is considered entangled.
- [opportunistic feeding](https://dosits.org/glossary/opportunistic-feeding/) - a type of foraging in which an animal feeds on a wide variety of prey and is able to adapt to whatever food becomes available.
- [Automatic Identification System (AIS)](https://dosits.org/glossary/automatic-identification-system-ais/) - an automated tracking system used to electronically identify and locate ships. AIS uses GPS-linked, very high frequency radio signals that allow for ship-to-ship and ship-to-shore information transfer. Information transmitted includes a ship's name, position, speed, heading, and other information. These details are transmitted multiple times each minute.
- [ecology](https://dosits.org/glossary/ecology/) - the scientific study of the relationship between organisms and their environment.
- [extrapolate](https://dosits.org/glossary/extrapolate/) - to estimate or expand unknown data based on known facts and/or observations.
- [mean](https://dosits.org/glossary/mean/) - the average of a set of measurements defined to be the sum of all of the measurements divided by the number of measurements.
- [variance](https://dosits.org/glossary/variance/) - an estimate of the variability of a set of measurements about the mean value; it is calculated by subtracting the mean from each of the measurements, squaring the differences, adding all of the squared differences together, and dividing by one less than the total number of measurements; the square root of the variance is the
- [standard deviation of the mean](https://dosits.org/glossary/standard-deviation-of-the-mean/) - an estimate of the variability of the mean value computed from a specific set of measurements; it is calculated by dividing the standard deviation of the measurements by the square root of the number of measurements; also often called the standard error of the mean.
- [sample](https://dosits.org/glossary/sample/) - a subset of the population.
- [population](https://dosits.org/glossary/population/) - the entire collection of individuals or items from which samples are drawn.
- [sample size](https://dosits.org/glossary/sample-size/) - the number of individuals or items in a subset or sample of the population from which estimates of various statistical measures of the whole population are calculated.
- [t-test](https://dosits.org/glossary/t-test/) - a statistic that compares the sample means with the standard deviations of the sample means to determine whether the two sample means are statistically different.
- [false positive](https://dosits.org/glossary/false-positive/) - an error when one concludes that there is a real difference between two means when, in fact, there is not; also called a Type I error.
- [false negative](https://dosits.org/glossary/false-negative/) - an error when one concludes that there is not a real difference between two means when, in fact, there is a difference; also called a Type II error.
- [Type I Error](https://dosits.org/glossary/type-i-error/) - an error when one concludes that there is a real difference between two means when, in fact, there is not; also called a false positive error.
- [Type II Error](https://dosits.org/glossary/type-ii-error/) - an error when one concludes that there is not a real difference between two means when, in fact, there is a difference; also called a false negative error.
- [null hypothesis](https://dosits.org/glossary/null-hypothesis/) - the hypothesis that there is not a real difference between the means of two data sets.
- [finfish](https://dosits.org/glossary/finfish/) - teleost bony fishes, in other words, not sharks/skates/rays, and not shellfish.
- [fishery](https://dosits.org/glossary/fishery/) - the industry or occupation devoted to the catching, processing, or selling of fish, shellfish, or other aquatic animals.
- [logarithmic](https://dosits.org/glossary/logarithmic/) - of, relating to, or expressed in terms of logarithms. A logarithm is the power to which a base, such as 10, must be raised to produce a given number.
- [ion](https://dosits.org/glossary/ion/) - an atom or a group of atoms that has an electric charge. Positive ions, or cations, are formed by the loss of electrons; negative ions, or anions, are formed by the gain of electrons.
- [gross tonnage](https://dosits.org/glossary/gross-tonnage/) - a measure of the cargo carrying capacity or the volume of a ship.
- [hydrofoil](https://dosits.org/glossary/hydrofoil/) - a vessel that is lifted partially above the water by wing-like structures mounted on struts below the hull of a boat.
- [mass stranding](https://dosits.org/glossary/mass-stranding/) - a stranding event where 2 or more animals, excluding mother-calf pairs, unless a third animal strands, strand together in time and place.
- [stranding](https://dosits.org/glossary/stranding/) - an event where an aquatic animal, especially a marine mammal, lands on a beach or becomes stuck in shallow water, is dead or sometimes alive, and probably in distress.
- [hypothermia](https://dosits.org/glossary/hypothermia/) - a condition where the body loses heat faster than it can produce it, causing one's body temperature to become dangerously low.
- [hyperthermia](https://dosits.org/glossary/hyperthermia/) - a condition where the body produces or absorbs more heat than it can dissipate, causing one's body temperature to become elevated to a potentially dangerous level.
- [stressor](https://dosits.org/glossary/stressor/) - anything that causes the body to respond by releasing stress hormones.
- [wave](https://dosits.org/glossary/wave/) - disturbance caused by the movement of energy through a medium
- [wavelength](https://dosits.org/glossary/wavelength/) - the length of one cycle of a wave (one crest and one trough)
- [vacuum](https://dosits.org/glossary/vacuum/) - a space from which all gas and other matter has been removed
- [velocity](https://dosits.org/glossary/velocity/) - the linear speed of an object in a specified direction.
- [vertebrate](https://dosits.org/glossary/vertebrate/) - having vertebrae or having a backbone or spinal column. Fish and humans are examples of vertebrates.
- [vestibular system](https://dosits.org/glossary/vestibular-system/) - a fluid-filled maze of canals and chambers inside the inner ear that helps maintain orientation and balance.
- [viscosity](https://dosits.org/glossary/viscosity/) - a molecule's resistance to motion
- [vocal fold ligament](https://dosits.org/glossary/vocal-fold-ligament/) - connective tissue that strengthens the vocal folds via stiffness and support
- [Weberian ossicles](https://dosits.org/glossary/weberian-ossicles/) - a series of bones which connect the swim bladder to the inner ear and carry vibrations between to the two, aiding in hearing.
- [surf zone](https://dosits.org/glossary/surf-zone/) - The zone within which waves approaching the coastline start breaking; also called the breaker zone.
- [alongshore flow](https://dosits.org/glossary/alongshore-flow/) - A surface current that flows parallel to the shore.
- [anemometer](https://dosits.org/glossary/anemometer/) - a weather instrument that measures wind speed.
- [swim bladder](https://dosits.org/glossary/swim-bladder/) - a gas filled organ that is primarily used for buoyancy control but is also important for hearing in some fishes.
- [piezoelectric effect](https://dosits.org/glossary/piezoelectric-effect/) - the ability of some materials (notably crystals and certain ceramics) to generate electricity in response to applied mechanical stress
- [tuned airgun array](https://dosits.org/glossary/tuned-airgun-array/) - multiple airguns of different, carefully selected volumes that are fired at the same time.
- [audiometric curve](https://dosits.org/glossary/audiometric-curve/) - a graph displaying the range of sounds that humans can hear.
- [inter-click interval](https://dosits.org/glossary/inter-click-interval/) - the time it takes an echolocation signal to be sent out and an echo to return, combined with the time the animal needs to receive and process that echo.
- [photophores](https://dosits.org/glossary/photophores/) - light producing organs that appear as bright spots on various marine animals, including fishes and cephalopods.
- [spatulate](https://dosits.org/glossary/spatulate/) - having a narrow base and a broad body (spade-shaped).
- [vertical migration](https://dosits.org/glossary/vertical-migration/) - a pattern of movement that some marine organisms undertake each day. Usually organisms move to shallow waters at night and return to deeper waters during the day.
- [Atlantic Undersea Test and Evaluation Center (AUTEC)](https://dosits.org/glossary/atlantic-undersea-test-and-evaluation-center-autec/) - a deep-water laboratory located in the Bahamas (in the Tongue of the Ocean (TOTO)) that is instrumented with a variety of acoustic beacons and sensors to provide testing, evaluation, and certification for U.S. Navy submarine captains and their crews, as well as the accuracy of their undersea weapons. A Marine Mammal Monitoring (M3R) system has
- [Southern California Offshore Range (SCORE)](https://dosits.org/glossary/southern-california-offshore-range-score/) - a state-of-the-art facility that provides training and testing services to the U.S. Navy’s Pacific Fleet. The underwater tracking range is located west of San Clemente Island, CA, and consists of 84 bottom-mounted hydrophones that provide a coverage area of approximately 660 square nautical miles. Similar to AUTEC, a Marine Mammal Monitoring (M3R) system has been
- [Pacific Missile Range Facility (PMRF)](https://dosits.org/glossary/pacific-missile-range-facility-pmrf/) - a U.S. Naval facility off the island of Kauai, Hawaii, that is the world's largest instrumented, multi-dimensional testing and training missile range. It is the only range in the world where submarines, surface ships, aircraft, and space vehicles can operate and be tracked simultaneously. There are over 1,100 square miles of instrumented underwater range and
- [accelerometer](https://dosits.org/glossary/accelerometer/) - a device that measures the vibration, or change in motion (acceleration) of a structure or organism. The force caused by vibration or a change in motion causes piezoelectric material within the device to be squeezed, which produces an electrical charge that is proportional to the force exerted upon it. Since the charge is proportional to
- [accuracy](https://dosits.org/glossary/accuracy/) - the degree of closeness of measurements of a quantity to its actual value.
- [underwater dB](https://dosits.org/glossary/underwater-db/) - the relative unit used to specify the intensity of an underwater sound. The phrase underwater dB is used on DOSITS to indicate decibels computed using root-mean-square (rms) pressure unless otherwise indicated. Underwater dB are referenced to a pressure of 1 microPascal (µPa), which is abbreviated as dB re 1 µPa. To be able to compare
- [transverse wave](https://dosits.org/glossary/transverse-wave/) - a disturbance in which the particles vibrate up-and-down and the energy moves left-and-right
- [spherical spreading](https://dosits.org/glossary/spherical-spreading/) - energy spreading out from a sound source in the shape of a sphere; the power is radiated equally in all directions from the sound source
- [spreading loss](https://dosits.org/glossary/spreading-loss/) - a decrease in the intensity of a wave as it spreads out from a source
- [spy-hopping](https://dosits.org/glossary/spy-hopping/) - a common whale activity in which they lift their heads above the surface of the water and observe what is happening on the surface. Whales will often spin around in order to observe in all directions.
- [squid](https://dosits.org/glossary/squid/) - mollusks of the family Cephalopoda that are a favorite food of the sperm whale
- [static diffusion](https://dosits.org/glossary/static-diffusion/) - when particles move from a region of higher concentration to a region of lower concentration
- [statistically significant](https://dosits.org/glossary/statistically-significant/) - findings of an experiment or study that have a low probability of being due to chance alone
- [statistics](https://dosits.org/glossary/statistics/) - mathematical analysis that is used to explain and compare numerical data. This analysis helps make broader generalizations about a population from a smaller number of specific observations.
- [stereo](https://dosits.org/glossary/stereo/) - short for stereophonic: a sound-reproduction system that uses two or more separate channels to give a more natural distribution of sound.
- [stereocilia](https://dosits.org/glossary/stereocilia/) - long, flexible hair-like structures that occur as a brush border on the surface of some membranes
- [streamers](https://dosits.org/glossary/streamers/) - a long (2000-6000 m) string of hydrophones typically used with air-gun arrays
- [subsonic](https://dosits.org/glossary/subsonic/) - a frequency that is below the audible range
- [substratum (substrate)](https://dosits.org/glossary/substratum-substrate/) - the surface that an organism grows on or is attached to
- [supersaturated](https://dosits.org/glossary/supersaturated/) - more highly concentrated than is normally possible under given conditions of temperature and pressure
- [Surveillance Towed Array Sensor System (SURTASS)](https://dosits.org/glossary/surveillance-towed-array-sensor-system-surtass/) - a passive sonar system used to listen for noises produced by submarines. The system consists of a long string of underwater hydrophones that are towed behind a ship and pick up sounds in the ocean.
- [swim bladder (also called an air bladder)](https://dosits.org/glossary/swim-bladder-also-called-an-air-bladder/) - an expandable, gas-filled sac that helps fish maintain buoyancy in the water. This organ is also important for hearing in some species of fish.
- [synapse](https://dosits.org/glossary/synapse/) - a junction between a nerve cell and another nerve cell or a nerve fiber or a sensory receptor
- [tectonic](https://dosits.org/glossary/tectonic/) - relating to the deformation of the earth's crust
- [tectorial membrane](https://dosits.org/glossary/tectorial-membrane/) - a membrane that covers the surface of the organ of Corti in the cochlea of the inner ear
- [telemetry](https://dosits.org/glossary/telemetry/) - measuring and transmitting data from a remote location
- [temperature](https://dosits.org/glossary/temperature/) - a measure of the atomic and molecular vibration in a substance, in degrees. The response of a solid, liquid, or gas to the input or removal of heat energy.
- [temporary threshold shift (TTS)](https://dosits.org/glossary/temporary-threshold-shift-tts/) - a temporary increase in the threshold of hearing (minimum intensity needed to hear a sound) at a specific frequency that returns to its pre-exposure level over time
- [terrestrial](https://dosits.org/glossary/terrestrial/) - something that lives on land as opposed to in the water. Some animals, such as sea lions spend time both on land and in the water, they are considered to be both terrestrial and marine.
- [territoriality/territorial](https://dosits.org/glossary/territorialityterritorial/) - behavior in which an organism, for example a fish, defends its home
- [test](https://dosits.org/glossary/test/) - the outer skeleton of a sea urchin. It is made up of plates that encircle the sea urchin. Spines of the sea urchin grow from the test.
- [Thalassia](https://dosits.org/glossary/thalassia/) - a broad-bladed seagrass occurring in shallow tropical and subtropical estuaries and nearshore marine waters
- [theory](https://dosits.org/glossary/theory/) - a hypothesis or group of hypotheses that have been consistently validated through scientific observations or experiments. Geology's theory of plate tectonics is an example of a well-documented and widely accepted theory.
- [thermocline](https://dosits.org/glossary/thermocline/) - a layer of water in an ocean or certain lakes, that separates warmer surface water from colder deep water. Temperature rapidly changes with depth in this region of the water column.
- [thermometry](https://dosits.org/glossary/thermometry/) - the measurement of temperature
- [threshold of pain](https://dosits.org/glossary/threshold-of-pain/) - the intensity level where sound is physically painful. Usually at 115-130 dB.
- [threshold shift](https://dosits.org/glossary/threshold-shift/) - an increase (worsening) in the threshold of hearing for an ear at a specified frequency
- [towfish](https://dosits.org/glossary/towfish/) - an instrument, such as a side scan sonar, that is towed behind a ship
- [transmitter](https://dosits.org/glossary/transmitter/) - an instrument that sends out slectrical signals
- [trill](https://dosits.org/glossary/trill/) - a fluttering sound that alternates rapidly with another note
- [ultrasonic](https://dosits.org/glossary/ultrasonic/) - sound waves that have a frequency that is higher than what humans can hear (i.e. greater than 20,000 Hz). Bats and dolphins use these high frequency sounds for communication and navigation.
- [ultrasound signal](https://dosits.org/glossary/ultrasound-signal/) - sound vibrations that have frequencies above the range of human hearing
- [sound source](https://dosits.org/glossary/sound-source/) - something that creates sound
- [rostrum](https://dosits.org/glossary/rostrum/) - upper jaw of whales that is elongated and looks like a beak
- [salinity](https://dosits.org/glossary/salinity/) - the total amount of salt dissolved in seawater; the units most often used are parts per thousand (ppt) but practical salinity unit (psu) is now the accepted standard in oceanography. An average salinity value for seawater is 35 ppt (psu) or 35 parts of salt in 1000 parts of water.
- [salt domes](https://dosits.org/glossary/salt-domes/) - a layer of salt in a domed structure that was formed beneath the Earth's surface by the movement of salt over long periods of time. Salt domes are often associated with oil and gas deposits.
- [sardines](https://dosits.org/glossary/sardines/) - small, silvery, slender fish of the herring family that have one short dorsal fin and no scales on their heads
- [Sargassum or Gulfweed](https://dosits.org/glossary/sargassum-or-gulfweed/) - a type of brown algae (of the genus Sargassum) that have a branching thallus (body) with lateral outgrowths differentiated as leafy segments, air bladders, or spore-bearing structures
- [scattered/scattering](https://dosits.org/glossary/scatteredscattering/) - the diffusion of the sonar signal in many directions through refraction, diffraction and reflection, primarily due to the material properties of the seafloor. Scattering is one of the causes of attenuation in sonar, resulting in signal weakening.
- [scattering](https://dosits.org/glossary/scattering/) - when the path of a sound wave is broken up by objects (volume scattering) or the sea floor or sea surface (boundary scattering)
- [school](https://dosits.org/glossary/school/) - a large group of marine animals, for example fish, that swim together. The appearance of a large number of individuals may ward off potential predators.
- [Sciaenidae](https://dosits.org/glossary/sciaenidae/) - family of fishes that contains approximately 270 species distributed in the Atlantic, Pacific, and Indian Oceans. This family is commonly known as the drums, which are renowned for their sound producing ability.
- [scientific method](https://dosits.org/glossary/scientific-method/) - the orderly process by which scientists ask questions about the natural world and test their observations
- [seismic](https://dosits.org/glossary/seismic/) - relates to an earthquake, earth vibration or volcano
- [seismic reflection](https://dosits.org/glossary/seismic-reflection/) - a technique for examining the layers of the seafloor that uses the sound energy that is reflected by different layers in the seafloor.
- [seismic refraction](https://dosits.org/glossary/seismic-refraction/) - a technique for examining the layers of the seafloor that uses the sound energy that is refracted by different layers in the seafloor.
- [sensorineural hearing loss](https://dosits.org/glossary/sensorineural-hearing-loss/) - hearing loss due to damage to the nerves or inner ear structures
- [sensory hair cells](https://dosits.org/glossary/sensory-hair-cells/) - bundles of hair like projections (cilia) located on the surface of the inner ear that become stimulated by movement of the otolith against them. Stimulation of the hair cells results in sending a signal to the brain which is interpreted as sound.
- [shelf-edged habitats](https://dosits.org/glossary/shelf-edged-habitats/) - ocean habitat on the edge of the continental shelf
- [shoal](https://dosits.org/glossary/shoal/) - a large school of fish
- [side scan sonar](https://dosits.org/glossary/side-scan-sonar/) - sonar is an acronym for sound navigation and ranging equipment. Sonar systems use sound waves to detect underwater objects by listening to the returning echoes. Side scan sonar uses the strength of the returning echo, not the travel time, to map the seafloor and identify objects on the seafloor.
- [signal](https://dosits.org/glossary/signal/) - sound that is used for a specific task, such as to convey information.
- [signal-to-noise (SNR) ratio](https://dosits.org/glossary/signal-to-noise-snr-ratio/) - the ratio that compares the received level of a sound signal and the background noise level. For example, it is easy to hear conversations in a quiet room, where the signal-to-noise ratio is high, but it is difficult to hear conversations at a noisy party, where the signal-to-noise ratio is low.
- [signal processing](https://dosits.org/glossary/signal-processing/) - analyzing sounds from a receiver to detect and classify sound sources
- [signature sound](https://dosits.org/glossary/signature-sound/) - a unique sound that is associated with a specific sound source
- [signature whistle](https://dosits.org/glossary/signature-whistle/) - tonal sounds produced by whales and dolphins that are unique to a particular individual and distinct from any other member of the group. Signature whistles provide a way to recognize individuals and help maintain group cohesion.
- [sirenians](https://dosits.org/glossary/sirenians/) - group of mammals that includes manatees and dugongs
- [SOFAR channel](https://dosits.org/glossary/sofar-channel/) - SOFAR stands for SOund Fixing And Ranging. The sound speed minimum at 800-1000 meters of water depth is called the deep sound channel or, more historically, the SOFAR channel.
- [sonic muscle - swim bladder](https://dosits.org/glossary/sonic-muscle-swim-bladder/) - a combined mechanism used by fishes to produce sound. The swim bladder is a gas filled organ primarily used for buoyancy control and is also important for hearing in some fishes. The sonic muscle is attached to the swim bladder. Rapid flexure of the sonic muscle against the swim bladder produces drum-like sounds commonly associated
- [soniferous](https://dosits.org/glossary/soniferous/) - sound producing
- [sonogram](https://dosits.org/glossary/sonogram/) - graphic presentation of a sound. A sonogram plots the frequency vs. time and represents the different intensity of the frequencies with different colors. It is similar to a contour map or bathymetric map where the different colors represent different water depths. Also called a spectrogram
- [sound channel](https://dosits.org/glossary/sound-channel/) - an area of slow sound speed that causes sound waves to become focused at this water depth
- [sound channel axis](https://dosits.org/glossary/sound-channel-axis/) - depth of the minimum sound speed within the sound channel. Sound waves cycle above and below the axis as they move through the sound channel.
- [sound field](https://dosits.org/glossary/sound-field/) - the level of sound at different distances and depths from the source
- [sound receptor](https://dosits.org/glossary/sound-receptor/) - something that receives sound; sound receiver
- [sound spreading loss](https://dosits.org/glossary/sound-spreading-loss/) - the decrease in intensity that occurs when a sound wave expands as it moves away from a source
- [Sound Surveillance System (SOSUS)](https://dosits.org/glossary/sound-surveillance-system-sosus/) - a network of hydrophones mounted on the seafloors of the North Atlantic and North Pacific oceans maintained by the US Navy
- [spawning](https://dosits.org/glossary/spawning/) - to produce, release, or deposit eggs for reproduction
- [spermaceti organ](https://dosits.org/glossary/spermaceti-organ/) - an elongated connective tissue sac in the forehead of the sperm whale that contains a waxy fluid called spermaceti
- [parallel](https://dosits.org/glossary/parallel/) - being an equal distance apart everywhere, extending in the same direction, never meeting or intersecting
- [perpendicular](https://dosits.org/glossary/perpendicular/) - being at right angles
- [pan bone](https://dosits.org/glossary/pan-bone/) - thin bone in the back of the lower jaw that helps transmit sound to the middle ear
- [pectoral fins](https://dosits.org/glossary/pectoral-fins/) - the uppermost of the paired fins on a fish
- [peak pressure/0-to-peak pressure](https://dosits.org/glossary/peak-pressure0-to-peak-pressure/) - the range in pressure between zero and the greatest pressure of the signal
- [peak-to-peak pressure](https://dosits.org/glossary/peak-to-peak-pressure/) - the range in pressure between the most negative and the most positive pressure of the signal
- [pectoral flipper](https://dosits.org/glossary/pectoral-flipper/) - forelimbs of whales and dolphins that are used for stability and steering. These appendanges are generally flattened and paddle-like. Humpback whales have very large pectoral flippers, reaching 5 m (15 ft) in length.
- [pectoral free rays](https://dosits.org/glossary/pectoral-free-rays/) - rays that are part of the fishes pectoral fins but are free from the actual fin skin. These rays aid in the movement of the fish.
- [pectoral girdle](https://dosits.org/glossary/pectoral-girdle/) - the bony or cartilaginous arch that supports the forelimbs of a vertebrate
- [pelagic species](https://dosits.org/glossary/pelagic-species/) - organisms that swim or drift in the water; these organisms are distinct from those living on or in the bottom sediments.
- [permanent threshold shift (PTS)](https://dosits.org/glossary/permanent-threshold-shift-pts/) - a permanent increase in the threshold of hearing (minimum intensity needed to hear a sound) at a specific frequency above a previously established reference level
- [pharyngeal](https://dosits.org/glossary/pharyngeal/) - teeth located in the gill or throat region
- [piezoelectric material](https://dosits.org/glossary/piezoelectric-material/) - a material that produces electrical charges when subjected to pressure changes
- [pinna, auricle](https://dosits.org/glossary/pinna-auricle/) - the ear flap or outer part of the ear that extends from the head. The pinna funnels sound down the outer ear canal to the eardrum.
- [plankton](https://dosits.org/glossary/plankton/) - relatively small organisms that drift or float passively in the water and are carried wherever currents and tides take them. Plankton are often microscopic and are an important food source for other aquatic organisms. There are two types of plankton- phytoplankton (plants and autotrophs) and zooplankton (animals).
- [plectrum](https://dosits.org/glossary/plectrum/) - part of the spiny lobster that is found underneath the files. It is a soft piece of tissue that is found at the base of the antennae. The plecta is what the lobster pulls over the files to produce sound
- [polyps](https://dosits.org/glossary/polyps/) - small marine invertebrates that have hard, cup-like, limestone skeletons. Polyps live in large colonies where they take-in the calcium from the ocean and to build a hard shell around themselves. The skeletons grow one on top of one another and as a result a coral reef is able to grow.
- [profile](https://dosits.org/glossary/profile/) - the change of an oceanographic variable with water depth
- [projector](https://dosits.org/glossary/projector/) - an instrument that sends out sound waves; consists of a transmitter and a transducer
- [projector arrays](https://dosits.org/glossary/projector-arrays/) - a collection of individual projectors used together to generate a directional sound beam
- [pure tone](https://dosits.org/glossary/pure-tone/) - a sound that consists of one single frequency
- [RAFOS floats](https://dosits.org/glossary/rafos-floats/) - floating instruments designed to move with a current and track the current's movements
- [ramp-up](https://dosits.org/glossary/ramp-up/) - gradually increasing the sound source level
- [recess](https://dosits.org/glossary/recess/) - hole, corner or niche. For example, a rock recess, a place surrounded by rocks where a fish can hide
- [rectified diffusion](https://dosits.org/glossary/rectified-diffusion/) - when acoustic energy causes supersaturated gas to be pumped into an existing small bubble, making the bubble increase in size
- [reflected wave](https://dosits.org/glossary/reflected-wave/) - the wave moving away from the reflector
- [reflector](https://dosits.org/glossary/reflector/) - any boundary between two media that causes the reflection of a wave
- [resonance](https://dosits.org/glossary/resonance/) - when sounds of specific frequencies cause air- or fluid-filled organs to vibrate with amplitudes that are large compared to the amplitude of incoming soundwaves
- [resonator](https://dosits.org/glossary/resonator/) - something that fills with sound and acts as a natural amplifier
- [rete mirabile](https://dosits.org/glossary/rete-mirabile/) - a tightly packed bundle of capillaries which works with the gas gland to force gases into the bladder
- [rorquals](https://dosits.org/glossary/rorquals/) - whales of the family Balaenopteridae which includes humpbacks, sei, minke, fin, blue and Bryde's whales. They have throat pleats or ventral grooves that expand when the whales gulp large amounts of water while feeding.
- [longitudinal wave](https://dosits.org/glossary/longitudinal-wave/) - a disturbance in which the particles and the energy move in the same direction
- [inner ear](https://dosits.org/glossary/inner-ear/) - the innermost part of the ear that is surrounded by the skull bone. It contains the organs of balance and hearing. The inner ear contains the vestibular system that helps maintain our balance. It also contains the cochlea that transforms sound waves into nerve impulses that are carried to the brain.
- [labyrinth](https://dosits.org/glossary/labyrinth/) - a complex system of interconnecting bony or membranous cavities, particularly those concerned with hearing and balance
- [lanugo](https://dosits.org/glossary/lanugo/) - the soft, downy hair that covers some newborn mammals; in Arctic seals, it is a white fur that is highly prized by seal hunters, most famously associated with the hunting of harp seal pups
- [lateral line](https://dosits.org/glossary/lateral-line/) - sensory organ, found in fishes, that runs long the length of their body. The lateral line allows fish to sense movement.
- [larynx](https://dosits.org/glossary/larynx/) - the upper part of the trachea (air passage) that contains the vocal folds
- [ligaments](https://dosits.org/glossary/ligaments/) - strong, flexible bands of tissue that hold two or more bones together at moveable joints. They help restrain the movement of bones at the joint.
- [localize](https://dosits.org/glossary/localize/) - determine the direction the sound is coming from.
- [LOFAR](https://dosits.org/glossary/lofar/) - Low Frequency and Ranging sonobuoy; a type of passive acoustic sonobuoy
- [loudness](https://dosits.org/glossary/loudness/) - how loud a person perceives a sound to be. Not the same as the intensity of the sound. The perceived loudness varies with frequency.
- [magnetic resonance imaging (MRI)](https://dosits.org/glossary/magnetic-resonance-imaging-mri/) - method of producing a three-dimensional image of object by recording the signals the object emits when placed in a magnetic field
- [mechanoreceptors](https://dosits.org/glossary/mechanoreceptors/) - sensory organs that cause response to displacement, pressure and vibrations
- [melon](https://dosits.org/glossary/melon/) - lipid-filled sac in the forehead of whales that helps to focus sound
- [mesopelagic boundary community](https://dosits.org/glossary/mesopelagic-boundary-community/) - small (less than 4 inches long) fishes, shrimps, and squids that live in the middle of the water column and near islands
- [middle ear](https://dosits.org/glossary/middle-ear/) - the air-filled cavity that lies between the outer ear and the inner ear. The middle ear contains the ossicles which conduct sound vibration from the eardrum to the inner ear.
- [migration](https://dosits.org/glossary/migration/) - movement of a group of animals from one location to another
- [mooring](https://dosits.org/glossary/mooring/) - equipment (often consisting of anchors and chains) which holds an item (such as a boat or underwater instrument) stable and secure in one place
- [morphology](https://dosits.org/glossary/morphology/) - the form and structure of an organism or any of its parts
- [multi-channel seismics](https://dosits.org/glossary/multi-channel-seismics/) - using multiple hydrophone arrays or streamers to record the reflected and refracted sounds from an air gun array
- [narrowband](https://dosits.org/glossary/narrowband/) - sounds made up of only a small range of frequencies
- [necropsies](https://dosits.org/glossary/necropsies/) - the examination and dissection of a body to determine the cause of death; autopsy
- [NeMO Net](https://dosits.org/glossary/nemo-net/) - New Millennium Observatory Network; a project, which records and transmits daily temperature and pressure readings from Axial Volcano
- [neuromasts](https://dosits.org/glossary/neuromasts/) - small, sensory receptors of arranged hair cells located along the lateral line, which respond to motion between the fish and the surrounding water
- [noise](https://dosits.org/glossary/noise/) - an unwanted sound or a sound that interferes with the perception of another signal, whether it be through recording or hearing.
- [non-vocal sounds](https://dosits.org/glossary/non-vocal-sounds/) - sounds made without the use of vocal folds or other body parts whose primary function is moving air for sound production. These sounds are typically made by slapping a body part on the water or land surface, or by forcefully clapping body parts together. Non-vocal sounds may be used to communicate acoustically.
- [normal line](https://dosits.org/glossary/normal-line/) - a line that is perpendicular (makes a 90 degree angle) to a surface
- [oceanographic variable](https://dosits.org/glossary/oceanographic-variable/) - a characteristic of the ocean that changes
- [octavo-lateralis system](https://dosits.org/glossary/octavo-lateralis-system/) - comprised of the lateral line and inner ear of fish; provides fish with balance, hearing, and the ability to feel vibrations from a distance
- [offspring](https://dosits.org/glossary/offspring/) - next generation or baby of a certain species
- [olfactory organ](https://dosits.org/glossary/olfactory-organ/) - an organ for smelling
- [omnidirectional](https://dosits.org/glossary/omnidirectional/) - having no directional component; producing or receiving sounds from all directions
- [omnivorous](https://dosits.org/glossary/omnivorous/) - organisms that eat both animals and plants
- [organ of Corti](https://dosits.org/glossary/organ-of-corti/) - the sensory part of the inner ear that converts sound signals into nerve impulses. Located on the basilar membrane, it contains sensory cells that transform vibrations into neural code for sound processing by the brain. It contains many important cells including the inner and outer hair cells.
- [ossicles](https://dosits.org/glossary/ossicles/) - three tiny bones - the incus (anvil), malleus (hammer), and stapes (stirrup) - that lie in the middle ear. The ossicles conduct sound across the middle ear to the inner ear by forming a bridge between the eardrum and the oval window.
- [otariids or eared seals](https://dosits.org/glossary/otariids-or-eared-seals/) - fur seals and sea lions that have visible ear flaps. They have an elongated neck and long front flippers. Their hind flippers can be turned forward for walking on land.
- [outer ear](https://dosits.org/glossary/outer-ear/) - the outermost part of the ear that is external to the ear drum or tympanic membrane. It directs sound waves down the air-filled ear canal onto the eardrum.
- [oval window](https://dosits.org/glossary/oval-window/) - a membrane-covered opening between the middle ear and the inner ear. The oval window is connected to the third ear ossicle (stapes) and passes sound vibrations to the inner ear.
- [pack ice](https://dosits.org/glossary/pack-ice/) - a large expanse of floating ice
- [equilibrium](https://dosits.org/glossary/equilibrium/) - the rest position of the particles in a medium
- [frequency](https://dosits.org/glossary/frequency/) - the rate of repetition of a regular event. The number of cycles of a wave per second. Expressed in units of Hertz (Hz)
- [Hertz](https://dosits.org/glossary/hertz/) - the unit of frequency; the number of cycles, or wavelengths, in a second (cycles/second)
- [intensity](https://dosits.org/glossary/intensity/) - the average amount of sound power (sound energy per unit time) transmitted through a unit area in a specified direction. The unit of intensity is watts per square meter. For simplicity, the magnitude of the intensity is often referred to as the intensity, without specifying the direction in which the sound is traveling.
- [hydrophone](https://dosits.org/glossary/hydrophone/) - an underwater microphone that will listen to, or pick up, acoustic signals. A hydrophone converts acoustic energy into electrical energy and is used in passive underwater systems to listen only.
- [decompression sickness](https://dosits.org/glossary/decompression-sickness/) - known as the bends, a condition that occurs in deep-sea divers caused by the formation of nitrogen bubbles in the blood and tissues following a sudden decrease in the surrounding pressure. This occurs when ascending rapidly from a deep dive and is characterized by severe pains in the joints and chest, skin irritation, cramps, and
- [delphinid](https://dosits.org/glossary/delphinid/) - cetaceans of the family Delphinidae, the most diverse of cetacean families. Includes oceanic whales and dolphins, such as, killer whales, pilot whales, common dolphins and bottlenose dolphins
- [detonation](https://dosits.org/glossary/detonation/) - to explode
- [DIFAR](https://dosits.org/glossary/difar/) - Directional Frequency Analysis and Recording device; passive acoustic sonobuoy
- [digital data](https://dosits.org/glossary/digital-data/) - information that is represented in a coded form, as a series of zeros and ones
- [directional](https://dosits.org/glossary/directional/) - producing or receiving sound only from certain angles or directions
- [dorsal fin](https://dosits.org/glossary/dorsal-fin/) - the main fin found on the back of fishes and some marine mammals. Some whales, such as the killer whale, have tall dorsal fins, while other whales (i.e. belugas and bowheads) have no dorsal fin.
- [drumming](https://dosits.org/glossary/drumming/) - to vibrate a muscle in, on, or near, the swim bladder that produces a loud, low-pitched grunt sound
- [ducts](https://dosits.org/glossary/ducts/) - internal passage involved in the flow of fluids through an organism
- [echo signature](https://dosits.org/glossary/echo-signature/) - a unique sonar return (reflection) that can be used to identify individual species of marine organisms, such as fish, or other submerged objects
- [echosounding](https://dosits.org/glossary/echosounding/) - the technique of measuring the depth of a body of water by means of an echosounder, an electrical depth sounder that uses sound echoes. The instrument emits sound waves that travel to the bottom of the ocean and are reflected back. Depth is determined by timing how long it takes the sound pulse to leave
- [ecological risk assessment](https://dosits.org/glossary/ecological-risk-assessment/) - the process of calculating the probability of adverse ecological effects
- [endangered](https://dosits.org/glossary/endangered/) - any species that is in danger of extinction
- [elasmobranchs](https://dosits.org/glossary/elasmobranchs/) - a group of fishes, including sharks, rays and skates, that has a skeleton made of cartilage rather than bone; they also do not have a swim bladder.
- [equal loudness curve](https://dosits.org/glossary/equal-loudness-curve/) - a graph of the perceived intensity (loudness) of sounds. The loudness of a sound is different for different frequencies.
- [extrapolation](https://dosits.org/glossary/extrapolation/) - using evidence and inferences from a similar situation to project information about a related event or process. Extrapolation can also be used to apply or transfer experimental observations from a model to the real world.
- [fecund, prolific](https://dosits.org/glossary/fecund-prolific/) - fruitful in offspring or vegetation
- [focal animal observations](https://dosits.org/glossary/focal-animal-observations/) - observations concentrated on individual animals that record everything they do
- [foraging](https://dosits.org/glossary/foraging/) - to search for food
- [foraging behavior](https://dosits.org/glossary/foraging-behavior/) - the way in which an animal searches for food; the process, or series of actions, that an animal goes through to find food
- [frequency spectrum](https://dosits.org/glossary/frequency-spectrum/) - a graph of a sound that plots the intensity of each frequency in the sound. Plural is spectra.
- [fright response](https://dosits.org/glossary/fright-response/) - responding out of fear
- [ganglion cells](https://dosits.org/glossary/ganglion-cells/) - nerve cells that have their cell bodies outside of the central nervous system (the brain and spinal cord). Auditory ganglion cells carry sound information from the inner hair cells to the auditory nerve.s
- [gas gland](https://dosits.org/glossary/gas-gland/) - a modification of the inner lining of the bladder, which works with the rete mirabile to force gases into the bladder
- [habituate](https://dosits.org/glossary/habituate/) - to become accustomed to something through repeated or prolonged exposure
- [harmonic frequency](https://dosits.org/glossary/harmonic-frequency/) - the part of a signal whose frequency is an integer multiple of the fundamental frequency. Harmonic frequencies are related to each other by simple whole number ratios, for example if the fundamental frequency is f, the harmonics have frequencies of 2f, 3f, 4f, etc.
- [Heard Island Feasibility Test (HIFT)](https://dosits.org/glossary/heard-island-feasibility-test-hift/) - an expedition to Heard Island in the southern Indian Ocean during which acoustic sources suspended below a ship transmitted acoustic signals to receivers around the globe. Heard Island was selected because signals transmitted from that location can reach both coasts of North America. HIFT showed that underwater acoustic signals could be received worldwide and serve
- [hearing generalist](https://dosits.org/glossary/hearing-generalist/) - a fish species in which the swim bladder aids very little or not at all in hearing sensitivity
- [hemorrhages](https://dosits.org/glossary/hemorrhages/) - flow of blood from a ruptured blood vessels; excessive bleeding
- [hermaphroditic](https://dosits.org/glossary/hermaphroditic/) - an animal or plant having both male and female reproductive organs
- [hydroacoustic](https://dosits.org/glossary/hydroacoustic/) - acoustics in water
- [hydrodynamic](https://dosits.org/glossary/hydrodynamic/) - of, relating to, or operated by the force of liquid in motion
- [hydrothermal vent](https://dosits.org/glossary/hydrothermal-vent/) - a hot spring on the seafloor
- [IES](https://dosits.org/glossary/ies/) - Inverted Echosounder; an instrument used to measure the temperature of the water column at a single point
- [incident wave](https://dosits.org/glossary/incident-wave/) - the wave moving towards the reflector
- [infrasonic](https://dosits.org/glossary/infrasonic/) - sound waves that have a frequency that is lower than what humans can hear (i.e. below about 20 hertz). Baleen whales, such as blue and fin whales, produce these low frequency sounds. The sounds may be used to communicate over long distances and to detect large-scale topography of the seafloor. On land, elephants also use
- [amplitude](https://dosits.org/glossary/amplitude/) - the maximum distance that a vibrating particle moves from its equilibrium; how much the medium is disturbed
- [amphibious](https://dosits.org/glossary/amphibious/) - living or able to live on land and in the water
- [angle of incidence](https://dosits.org/glossary/angle-of-incidence/) - the angle that the incident wave makes with a line perpendicular or normal to the reflecting surface
- [angle of reflection](https://dosits.org/glossary/angle-of-reflection/) - the angle that the reflected wave makes with a line perpendicular or normal to the reflecting surface
- [animated frequency spectrum](https://dosits.org/glossary/animated-frequency-spectrum/) - An animated frequency spectrum is a series of frequency spectra that show just the frequencies present at each moment in time. You can see what frequencies are associated with each part of a sound.
- [anthropogenic](https://dosits.org/glossary/anthropogenic/) - caused by humans
- [Aristotle's lantern](https://dosits.org/glossary/aristotles-lantern/) - claw-like mouth on a sea urchin that contains five calcium carbonate teeth that are used for feeding
- [array elements](https://dosits.org/glossary/array-elements/) - a single hydrophone in a receiving array or a single projector (sound source) in a projector array
- [arthropods](https://dosits.org/glossary/arthropods/) - invertebrates of the phylum Arthropoda that have jointed appendages and a chitinous, segmented exoskeleton. Arthropods include insects, spiders, crabs, and lobsters.
- [attenuation](https://dosits.org/glossary/attenuation/) - the decrease in the intensity of a wave due to the loss of acoustic energy to heat energy
- [auditory fatigue](https://dosits.org/glossary/auditory-fatigue/) - when the intensity level or duration of sound overwhelms the hair cells so they cannot respond to sounds appropriately
- [auditory meatus or ear canal](https://dosits.org/glossary/auditory-meatus-or-ear-canal/) - an air-filled canal that leads from the ear flap to the ear drum. It helps direct sound waves to the ear drum.
- [axial muscles](https://dosits.org/glossary/axial-muscles/) - folded muscle segments that, when contracted, produce a wavelike motion that moves the fish through the water
- [baleen](https://dosits.org/glossary/baleen/) - series of horny plates that hang from the gums of the upper jaw of some large whales (called Mysticetes). The baleen is made from the same materials as human hair and fingernails. It is used to filter small bits of food from the water.
- [baleen whales](https://dosits.org/glossary/baleen-whales/) - These large cetaceans are usually more than 9.1 m (30 ft) long and can be found throughout the ocean. Instead of teeth, mysticetes have a series of horny plates called baleen. The baleen is made from the same materials as human hair and fingernails. The baleen plates hang from the gums of the upper jaw
- [basilar membrane](https://dosits.org/glossary/basilar-membrane/) - a membrane in the cochlea of the ear that vibrates in response to sound. As sound vibrations progress down the ear, a fluid wave that is created by the movement of the third ossicle, the stapes, moves the basilar membrane. The basilar membrane is the part of the cochlea that separates sounds according to their
- [beacon](https://dosits.org/glossary/beacon/) - an acoustic signaling device that continually sends out a repetitive signal. Acoustic beacons, sometimes called pingers, are used to mark the locations of underwater objects.
- [bearing](https://dosits.org/glossary/bearing/) - measurement of direction; the angle, with respect to magnetic north, to where the target is located
- [biologically significant](https://dosits.org/glossary/biologically-significant/) - an action or activity that affects an animal's ability to grow, survive, or reproduce.
- [biomass](https://dosits.org/glossary/biomass/) - measure of the amount of living material in an area, usually expressed in units of weight per unit volume
- [bowriding](https://dosits.org/glossary/bowriding/) - a common activity of dolphins and other cetaceans in which marine mammals swim in front of a vessel, riding or surfing on the pressure wave created by the vessel
- [broadband](https://dosits.org/glossary/broadband/) - a sound signal that includes acoustic energy across a wide range of frequencies.
- [bubble feeding](https://dosits.org/glossary/bubble-feeding/) - a feeding process where whales trap a school of prey (fish or krill) by blowing a series of bubbles as the whales swim to the surface. The bubbles form a curtain that rises to the surface of the water and concentrates the prey in the center. The whales charge through with their mouths open to
- [buoyancy](https://dosits.org/glossary/buoyancy/) - the upward force on a free floating or submerged object, independent of the object's weight; gives submerged objects the weightless appearance.
- [bycatch](https://dosits.org/glossary/bycatch/) - the harvest of fish (or any marine organism) other than the species for which the fishing gear was set
- [byssal threads](https://dosits.org/glossary/byssal-threads/) - string like substance that is secreted by mussels to allow the mussel to attach to hard substrates like rocks
- [caldera](https://dosits.org/glossary/caldera/) - depression formed at the summit of a volcano
- [callosities](https://dosits.org/glossary/callosities/) - thick, white patches of hardened skin, called chitin, that are covered with tiny crustaceans, called whale lice." These patches are found on the heads
- [canine teeth](https://dosits.org/glossary/canine-teeth/) - sharp, fang-like teeth adapted for capturing and penetrating prey
- [capillaries](https://dosits.org/glossary/capillaries/) - the smallest of the network of blood vessels throughout an organism
- [chordotonal organs](https://dosits.org/glossary/chordotonal-organs/) - for Crustaceans, they are located at the joint segments and they serve as mechanoreceptors (sensory organs).
- [cichlids](https://dosits.org/glossary/cichlids/) - family (Cichlidae) of freshwater fishes found throughout tropical and subtropical waters of the Americas, Africa and parts of Asia
- [cilia](https://dosits.org/glossary/cilia/) - hair cells of the neuromast
- [click train](https://dosits.org/glossary/click-train/) - rapid sequence of clicks, produced by whales and dolphins, that are associated with echolocation. The clicks are emitted from the melon of the whale.
- [climatologist](https://dosits.org/glossary/climatologist/) - a scientist who studies climate
- [clupeids](https://dosits.org/glossary/clupeids/) - fish belonging to the herring family
- [coalesced](https://dosits.org/glossary/coalesced/) - fused or grown together
- [corticosteroid](https://dosits.org/glossary/corticosteroid/) - a type of hormone produced by the adrenal glands. Corticosteroids levels may be elevated as a response to stress.
- [courtship](https://dosits.org/glossary/courtship/) - behaviors in animals, that are used to initiate mating
- [crustaceans](https://dosits.org/glossary/crustaceans/) - a class of mainly aquatic, gill-breathing arthropods such as crabs, lobsters, shrimp, and barnacles. They usually have a hard exoskeleton and two pairs of antennae.
- [cupula](https://dosits.org/glossary/cupula/) - gel-like cover of cilia in the neuromast
- [cylindrical spreading](https://dosits.org/glossary/cylindrical-spreading/) - energy spreading out from a sound source in the shape of a cylinder; no energy radiates above the top or below the bottom of the cylinder
- [acoustic fish tag](https://dosits.org/glossary/acoustic-fish-tag/) - a transmitter implanted or attached to a fish to monitor fish movement
- [acoustic modem](https://dosits.org/glossary/acoustic-modem/) - a wireless communication device used to transmit data and information through the ocean
- [acoustic propagation models](https://dosits.org/glossary/acoustic-propagation-models/) - conceptual and numerical models that compute how sound travels through the water, taking into account many variables such as water temperature, salinity, bottom topography, etc.
- [acoustic release](https://dosits.org/glossary/acoustic-release/) - a device which holds onto the anchor of a buoyant instrument until it is commanded to release it
- [acoustical shadowing](https://dosits.org/glossary/acoustical-shadowing/) - a condition that occurs when refraction or reflection prevents direct sound waves from reaching a region (called a shadow zone)
- [acoustic telemetry](https://dosits.org/glossary/acoustic-telemetry/) - to transmit acoustic signals automatically and at a distance, as between a ground station and an artificial satellite, space probe, or the like, especially in order to record information, operate guidance apparatus, etc
- [acoustic trauma](https://dosits.org/glossary/acoustic-trauma/) - severe traumatic injury from sound
- [acoustic tomography](https://dosits.org/glossary/acoustic-tomography/) - uses the travel time of sound in the ocean to measure the temperature of the ocean over large areas
- [ADCP](https://dosits.org/glossary/adcp/) - Acoustic Doppler Current Profiler; an instrument used to measure the current using acoustic sound and the knowledge of the Doppler effect

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