An inexpensive passive acoustic system for recording and localizing wild animal sounds

An inexpensive animal recording and tracking system was designed, which uses sound-recording buoys deployed at several locations simultaneously in a passive hydrophone array. Each buoy contains a global positioning system (GPS) Location logger, a stereo digital audio tape (DAT) recorder with a hydrophone connected to one channel, and a VHF radio signal for time synchronization connected to the second channel. In a calibration test, three buoys were deployed in triangle formation at 1.8-km spacing. Light bulb implosions were localized to an accuracy of 60 m at the array center. These buoys are far less expensive than most marine acoustic tracking systems. The instrument package can be used for drift, moored, or terrestrial applications.