Midwater Assessment and Conservation Engineering Program

Acoustic returns showing pollock schools. Scientists in the Midwater Assessment and Conservation Engineering (MACE) Program have historically assessed the status of walleye pollock and Pacific hake stocks from the coasts of California to the Bering Sea since 1977. The MACE Program continues to assess walleye pollock in the north Pacific and Bering Sea, while the Northwest Fisheries Science Center has continued Pacific hake assessments biennially since 2003. Pollock assessment is conducted with midwater trawl surveys combined with acoustic (echo integration) technology to develop distribution and abundance time series. Research is also conducted on fishing gear performance and on fish behavior during the capture process in order to develop methods that reduce bycatch in commercial fishing operations.

Twin trawl being brought on deck. Walleye pollock resources in the north Pacific and Bering Sea support the largest single commercial fishery in the United States and one of the largest commercial fisheries in the world. Surveys to determine the pollock abundance and distribution are conducted to support NMFS fishery management responsibilities for the territorial sea and to meet U.S. international fishery management commitments for the Convention on the Conservation and Management of Pollock in the Central Bering Sea.

Winter surveys of spawning pollock abundance have been conducted annually in the Bogoslof Island area of the Bering Sea since 1988 and in the Shelikof Strait area of the Gulf of Alaska since 1981. Assessment of summer pollock abundance in the Bering Sea has occurred routinely since 1979, while Pacific hake abundance off the West Coast was surveyed from 1977 to 2001. Pollock surveys continue to be conducted in conjunction with bottom trawl surveys for other groundfish species, and often carried out in cooperation with foreign scientists and foreign research vessels. The acoustic/midwater trawl survey estimates of distribution and abundance are documented in various scientific reports and are incorporated into stock assessment advice to fishery management councils, international fishery management organizations, and industry.

NEW! (Updated 31 January 2013) NOAA Protocols for Fisheries Acoustics Surveys and Related Sampling

Note! Trawl Gear Modification—Preserving Fish Habitat in the Bering Sea

Seafloor Videos from Bering Sea Research Project