A stereo acoustic event recorder for monitoring abundance and movements of dolphins and porpoises

A multi-platform ultrasonic event recorder for towing and stationed monitoring of cetaceans was developed. A stereo acoustic event recorder (A-tag) was originally developed to observe biosonar behavior by tagging on dolphins and porpoises in the wild. In recent years, A-tag has been applied for the acoustic transect to count the number of dolphins and porpoises, and for the long term stationed observation.