Abstract: The identity of an aquatic organism is determined by a signature derived from a broadband acoustic signal transmitted and received by a broadband transducer or transmitted by a an broadband acoustic transmitter and received by an array of broadband acoustic receivers. The signature is a set of classifier coefficients created from a training processing that learns to discriminate between various size/taxa of aquatic life forms using features extracted from the received broadband echoes. The signature database used for classification during operation is stored on a portable storage medium. The degree to which the signals collected from an unknown aquatic life form matches the predefined known aquatic life form is then reported to a utilizing device.