Hydroacoustics are used by the National Marine Fisheries Service for fisheries management. The principal objective in hydroacoustics is to collect target strength data for use in scaling echo integration data, thereby estimating the absolute abundance of a particular target fish species. On the Miller Freeman, the centerboard-mounted acoustic system is calibrated using standard sphere techniques. The echo integrator data is then compared with midwater and demersal trawl data to determine the distribution, biomass and biological composition of the target species.

Hydroacoustic surveys cover the Shelikof Strait, and Southern Alaska Peninsula shelf waters, plus the Bering Sea. Winter-spring assessments are made of these waters, with specific focus on the eastern shelf and Blogoslof area of the Bering Sea and the Shumagin Islands to Shelifkof Strait of the Southern Alaska Peninsula/Kodiak Island waters. Summer and winter surveys are also completed as part of the multi-lateral management of Bering Sea resources. These studies involve Russian, Korean, Chinese and Japanese scientist, as well as the US.

A special Bering Sea survey ranging from the US Bering to the Russian Coast is conducted with the assistance of Japan and Russia. This project consists of intership calibration of the acoustic systems aboard the Miller Freeman and the Japanese resesarch vessel KYOWA MARU (shown above) and hydroacoustic transit lines. Scientists from Russia, China, Poland, and South Korea participate in various capacities aboard the Miller Freeman and KYOWA MARU.