Fishtracker uses underwater acoustics to track the movements of individual fish living at Redfish Rocks.  

A grid of hydrophones, or acoustic receivers, is arranged so that  tagged fish can be detected anywhere within the study area.  Small transmitter tags are surgically implanted in the fish’s abdominal cavity.  Each tag emits unique coded signals identifying the fish and its depth. 

These signals are detected when the fish swims near a receiver, and its identity and depth are recorded at that location. 

These data are periodically downloaded from the receivers, and used to analyze the movement patterns of tagged fish.