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Fisheries acoustic research is conducted from a variety of platforms. The most common is a traditional research vessel, with the echosounders mounted on the ship's hull or in a drop keel. If the vessel does not have permanently installed echosounders, they may be deployed on a pole mount attached to the ship's side, or on a towed body or ...
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.
Output of a computer model of underwater acoustic propagation in a simplified ocean environment. A seafloor map produced by multibeam sonar. Underwater acoustics (also known as hydroacoustics) is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries.
A long-range acoustic device (LRAD), acoustic hailing device (AHD) or sound cannon is a specialized loudspeaker that produces sound at high power for communicating at a distance. It has been used as a method of crowd control , which has caused permanent hearing damage , having an extremely high decibel capacity (up to 160 dB measured at one ...
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 signals are the preferred communication tool for researchers who wish to track fish and wildlife in marine habitats in real time. As with radio, acoustic telemetry requires transmitters to send signals and receivers to hear them. The transmitters are electronic tags that emit a series of sound pulses into the surroundings.
The western North Atlantic showing the locations of two experiments that employed ocean acoustic tomography. AMODE, the "Acoustic Mid-Ocean Dynamics Experiment" (1990-1), was designed to study ocean dynamics in an area away from the Gulf Stream, and SYNOP (1988-9) was designed to synoptically measure aspects of the Gulf Stream.
A turtle excluder device (TED) is a specialized device that allows a captured sea turtle to escape when caught in a fisherman's net. In particular, sea turtles can be caught when bottom trawling is used by the commercial shrimp fishing industry .