Ecosystem components in the Bering sea convention area: results from studies and fisheries prospective

Abstract

Recent features in oceanography, forage base, and biological diversity, as well as fisheries prospective in the Bering Sea Convention area are considered. Since 1950, a sharp increase in water temperature has been observed, and thermal regime shifts occurred in 1977 and 2014. Composition and structure of zooplankton communities are virtually the same as in the western Bering Sea basin. Zooplankton community is comprised by a small number of widely distributed species, which belong to macrozooplankton and constitute a valuable food source for upper trophic levels. Nekton biomass is small, an order of magnitude lower than on the shelf. Neighboring continental slope and underwater ridges, as well as seasonal migrations of lower boreal and lower boreal-subtropical species support high species richness of nekton community. Pelagic and benthopelagic species of fish and squid, which occur on the shelf and slope, usually do not migrate into the Convention area in large quantities, except for walleye pollock, which was actively harvested in this area in 1983–1992. However, in the up-coming years, it is impossible to resume pollock fishery in the Convention area, based on the modern state of pollock resources.