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Fisheries acoustics includes a range of research and practical application topics using acoustical devices as sensors in aquatic environments. Acoustical techniques can be applied to sensing aquatic animals , zooplankton , and physical and biological habitat characteristics.
Acoustic tags are small sound-emitting devices that allow the detection and/or remote tracking of organisms in aquatic ecosystems. Acoustic tags are commonly used to monitor the behavior of fish. Studies can be conducted in lakes, rivers, tributaries, estuaries or at sea.
The devices have also been employed to keep marine mammals away from fishing nets. [2] The devices are known as acoustic harassment devices (AHDs) and acoustic deterrent devices, which are smaller AHDs [3] or intended as an awareness tool to warn species to the presence of danger rather than as a tool of harassment at a much louder level. [4]
Acoustic survey in fishing is one of the research methods that can detect the abundance of target species using acoustic detectors. For example, many pelagic fisheries are generally very scattered over a broad ocean and difficult to detect. Hence survey vessel with acoustic detector emits sound waves to estimate the density of plankton and fish ...
Collected acoustic data is "stamped" with geographic information for precise positional information (coordinates and time). This enables analysis and incorporation of the results into a Geographic Information System (GIS) for further analysis, correlation with other variables, mapping, and display.
Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. [4] Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation, [5] and sodar (an upward-looking in-air sonar) is used for atmospheric investigations.
Passive acoustics is the action of listening for sounds, often at specific frequencies or for purposes of specific analyses. It is often used for passive acoustic monitoring (PAM), the act of recording animal and environmental sounds through the use of acoustic sensors for the purpose of tracking animals and answering other ecological questions.
An autonomous recording unit (ARU) is a self-contained audio recording device that is deployed in marine or terrestrial environments for bioacoustical monitoring. The unit is used in both marine and terrestrial environments to track the behavior of animals and monitor their ecosystems.