Active vs Passive tracking Acoustic telemetry includes both passive acoustic telemetry where a network of static receivers detects animals moving through their environment, and active acoustic tracking where an individual animal is followed by a boat with a mobile receiver.

Transmitters are electronic tags that broadcast a series of “pings” (sound pulses) into the surrounding water. Tags are either surgically implanted or attached externally to a fish of interest so that once released into the wild, a tagged fish can be “heard” by any receiver within range.

Receiver costs depend on technology. Autonomous receivers are around $8,000 to $9,000 and cables receivers are about $19,000. The receivers have a lifespan of several years.

Acoustic tags permit collecting data (most often individual identification codes, depth or temperature) from a single fish equipped with an ultrasonic tag that generates sound by driving an annular ceramic transducer at its resonant frequency.