Specialized tools for biological assessment using split beam hydroacoustics

The science of fisheries acoustics and its applicability to resource management have evolved over the past several decades. The use of hydroacoustics for the assessment of fisheries resources is well established and split beam echosounders are now the standard instrument of scientific fisheries acoustics. To augment the information gained from mobile hydroacoustic surveys, researchers have developed innovative methods and devices to facilitate the use of split beam echosounders in new situations and environments. This document provides a description of three recent inventions that facilitate the use of split beam echosounders in non-conventional application; a hybrid split beam and imaging sonar system tested for defense related applications, an autonomous, submersible echosounder for long-term seafloor observation, and a towed echosounder specifically engineered for use with a self-propelled, autonomous surface vehicle.