2013 eastern Bering Sea continental shelf bottom trawl survey of groundfish and invertebrate resources

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 encompasses a major portion of the eastern Bering Sea shelf (depths between 20 - 200 m) from the Alaska Peninsula north to approximately the latitude of St. Matthew Island (60° 50' N). In 2013, two chartered trawlers, the 40-m FV Aldebaran and the 43.5-m FV Alaska Knight, surveyed this area. Demersal populations were sampled by trawling for 30 minutes at stations centered within 37.04 × 37.04 km (20 × 20 nmi) grids covering the survey area. At each station, species composition of the catch was determined, and length distributions and age structure samples were collected from ecologically and commercially important species. Three-hundred seventy-six standard survey stations were successfully sampled. A total of 93 fish species and 256 invertebrate taxa were identified in catches from the EBS survey . The combined biomass of walleye pollock (Gadus chalcogrammus), yellowfin sole (Limanda aspera), and northern rock sole (Lepidopsetta polyxystra) was 8.6 million metric tons (t) which was 71% of the total fish biomass. The biomass of invertebrates was primarily composed of echinoderms (1.3 million t) and crustaceans (0.9 million t). Survey results presented in this report include abundance estimates for fishes and invertebrates, geographic distributions and size compositions of selected fish species, and contour plots of surface and bottom temperatures during the survey sampling period. Appendices provide station data, catch data summarized by station, taxon listings, and detailed analyses of abundance and biological data of the sampled populations. [doi:10.7289/V5/TM-AFSC-331 (http://dx.doi.org/10.7289/V5/TM-AFSC-331)]

http://doi.org/10.7289/V5/TM-AFSC-331

Public Domain