Structure and spatial variation of bottom fish communities of the northwestern Bering Sea

Abstract

According to results of integrated record summer-autumn trawl surveys performed in 2004, 2005, and 2008 in the shelf-continental region of the northwestern Bering Sea from Cape Olyutorsky to Bering Strait in the range of depths 14–563 m, eight bottom communities of fish and fish-like were distinguished and their structure was described. In the composition of communities, 142 species from 29 families were recorded, among which Cottidae, Pleuronectidae, Zoarcidae, Agonidae, Stichaeidae, and Liparidae dominate by the number of species. According to biotopic belonging, bottom fish of elittoral, mesobenthal, and sublittoral complexes dominate in catches; according to zoogeographic belonging, wide boreal, arctic-boreal, and high boreal species dominate. Spatial change in the species structure of fish communities proceeds in correspondence with main regularities of life distribution in the ocean—principles of vertical and latitudinal zonality. The strongest relation of spatial variation of bottom fish communities was established with depth. Using multivariate nonmetrical scaling, five fish communities corresponding to different bathymetric ranges (sublittoral, elittoral, transitory shelf-bathyal, α-bathyal, and β-bathyal) were distinguished. Within sublittoral, elittoral, and shelf-bathyal communities, latitude zonal groups of Olyutorsky-Navarin and Anadyr regions having a lower hierarchic status were distinguished. In an interannual aspect, stability of the number of separated bottom fish communities and similarity of their spatial distribution in the examined sea areas is traced.