Fish telemetry and positioning from an autonomous underwater vehicle (AUV)

We assessed telemetry of transmittertagged fishes from an autonomous underwater vehicle with an attached hydrophone/datalogger that procesed code-division-multiple-access acoustic signals. Geolocation estimates used synthetic aperture and relative sound strength mapping. Transmitters could be detected at all angles relative to the AUV heading and as far as 2 km distant. Signal reception patterns from tagged Atlantic sturgeon, a large nektonic fish, were similar to that of moored reference tags but those from tagged winter flounder, a small benthic fish, were reduced in range due to burying behavior.The effectiveness of synthetic aperture and signal strength mapping techniques to geolocate tags were sensitive to the AUV’s path past or around the tag and complement each other as preferable solutions in different circumstances. Strategies of AUV search path for telemetry need to be explored further.