Surface Trawls

Near-Surface Fish Abundance and Distribution

Ed Farley and Alex Andrews

Objectives – (1) Assess the current status of pelagic fish and invertebrate communities and collect biological samples for further genetic, energetic, and trophic analyses, (2) compare results to earlier studies in the Chukchi Sea and to adjacent regions (Bering Sea).

There has been limited sampling of pelagic fishes in the Chukchi Sea, but an AFSC survey during early September 2007 (Moss et al. 2009b) indicated that pink (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) from the Arctic region and several marine/forage fish species (Pacific sand lance (Ammodytes hexapterus), Pacific herring (Clupea pallasi), saffron cod, Arctic cod, and pricklebacks utilize the region. The gear used in this study allows direct comparisons with results from this earlier survey and from similar surveys conducted on the eastern Bering Sea shelf since 2000. Near surface fish will be captured using a Cantrawl 400-580, rigged to fish from near surface to 20-m depth. All fish will be identified to the lowest taxonomic level and will be enumerated and weighed to compute catch per unit effort for assessing relative abundance and biomass. Biological measurements on individual fish include length, weight, caloric content (energy density; Moss et al. 2009a), isotopic composition (C/N ratio; trophic status; Kline et al. 2008), and stomach contents as described below.

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