Features of species composition and abundance of nekton community in the upper epipelagic layer of the North-West Pacific in early summer season
Structure of nekton community in the upper epipelagic layer is considered on the data of trawl surveys conducted in the North-West Pacific and adjacent waters in the early summers of 2004-2009. Intra-seasonal succession of the community and its changes under environmental conditions are described. The community included 66 species of fish and 22 species of cephalopods. Its biodiversity was lower in coastal areas and higher in deep waters. Mesopelagic species dominated by biomass amounting to 40-60 % of the total biomass of nekton, the portion of pacific salmons was 17-37 %. Mean biomass of nekton in the epipelagic layer within the studied area was 2431 thousand tons; in the last year (2009) it was close to this value.