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Acoustic tags are small sound-emitting devices that allow the detection and/or remote tracking of fish in three dimensions for fisheries research. Acoustic telemetry (including acoustic tags) are commonly used to monitor the behavior of fish. Studies can be conducted in lakes, rivers, tributaries, estuaries or at sea. Acoustic tag tracking technology allows researchers to view 3D fish tracks in real-time with sub-meter resolution. Acoustic tags have been employed to help public utility agencies, private firms, and state and federal agencies meet fisheries regulations as defined by the Federal Regulations and Oversight of Energy (known as FERC ). Acoustic tags come in an assortment of sizes and weights. To-date, the smallest acoustic tag successfully employed to provide fish behavior data in three dimensions was approximately 0.65 grams (tracking a juvenile salmonid at a length of 125 mm). Tag size increases significantly when tracking larger fish for longer periods of time (i.e. sturgeon). ==Overview== Acoustic tags allow researchers to: * Conduct Fish Survival Studies * Monitor Fish Migration/Passage/Trajectory * Track Fish Behavior in Two or Three Dimensions (2D or 3D) * Measure Bypass Effectiveness at Dams and other Passages * Observe Predator/Prey Dynamics and More Acoustic Tags transmit a signal made up of acoustic pulses or "pings" that sends location information about the tagged fish to the hydrophone receiver. By tying the received acoustic signature to the known type of programmed signal code, a specific fish is identified. The transmitted signal can propagate up to 1 km (in freshwater). Each "ping" comes at a predetermined interval. The signals are encoded for strength to improve range and resolution. Thus, an array of receivers allows the user to record the movement of a particular fish over many kilometers. Unique to Acoustic Tags is the capability to have over 100,000 user-specified individual tag ID codes with battery lives up to four years. These variables allows a custom fit for unique projects. By determining the sound's time of arrival at each hydrophone, the 3D position of the fish can be calculated. The hydrophone receiver picks up the sound signal and converts it to data that researchers use to plot the resulting tag positions in three dimensions, in real-time. Using a post processing software, such as ''MarkTags'', takes that data and delivers the end result, the 3D track. Acoustic tags can be attached to, gastrically inserted in or surgically implanted into fish (or almost any aquatic life). Several different types of methods are used to attach the tag to the fish. The tag may be embedded in the fish by cutting a small incision in the abdominal cavity of the fish (surgical implantation), or put down the gullet to embed the Acoustic Tag in the stomach (gastric implantation). External attachment using adhesive compounds is typically not used for fish as scale fluids do not allow for any successful attachment to scale tissue. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Acoustic tag」の詳細全文を読む スポンサード リンク
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