Determination of fish size distributions and areal densities using broadband low-frequency measurements

Abstract

Broadband low-frequency measurements have been used in conjunction with a fish swimbladder scattering model to determine size distributions and areal densities of well-known populations of dispersed fishes. The method has also been used to identify and estimate the abundance of deep-dwelling fishes that are generally beyond the range of high-frequency echo-sounders. It can also be used to examine swimbladder behavior. Results on five fish species in three widespread locations are presented to demonstrate the capabilities of the method.