Results of the 2007 Eastern Bering Sea Continental Shelf bottom trawl survey of groundfish and invertebrate resources

Abstract

The Resource Assessment and Conservation Engineering Division of the Alaska Fisheries Science Center conducts annual bottom trawl surveys to monitor the condition of the demersal fish and crab stocks of the eastern Bering Sea continental shelf. The standard study area, surveyed each year since 1979, encompasses a major portion of the eastern Bering Sea shelf between the 20-m and the 200-m isobaths and from the Alaska Peninsula north to approximately the latitude of St. Matthew Island (60°50'N). In 2007, two chartered trawlers, the 40-m FV Arcturus and the 40-m FV Aldebaran surveyed this area.

Demersal populations were sampled by trawling for 30 minutes at stations centered within 20 × 20 nautical mile grids covering the survey area. At each station, species composition of the catch was determined. Length distributions and age structure samples were collected from ecologically and commercially important species.

All 356 standard survey stations were sampled successfully. Twenty additional survey stations were sampled northwest of the standard survey area primarily to investigate the distribution and abundance of walleye pollock and opilio crabs. Walleye pollock, yellowfin sole, and rock sole dominated fish biomass estimates (8.3 million metric tons combined). A total of 179 invertebrate species were identified to the species level in the survey.

Survey results presented in this report include abundance estimates for fish and invertebrates, geographic distributions of important fish species and size composition of principal fish species, and contour plots of surface and bottom temperatures during the survey sampling period. Appendices provide station data, summarized catch data by station, species listings, and detailed analyses of abundance and biological data of the sampled populations.

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