Benthic invertebrate macrofauna of the Eastern Continental shelf of the Bering and Chukchi Seas

Abstract

The overall view presented by this study is of closely interrelated Bering/Chukchi benthic community system that extends unbroken over the entire continental shelf, with the Chukchi Sea benthos probably relying heavily on the Bering Sea for both food supply and possibly recruitment. Indications are that this is a highly productive and relatively stable benthic system comprised of at least eight major faunal zones of considerable complexity. The environmental factor correlating most strongly with the distribution of these faunal zones and with distribution of individual major species appears to be sediment type, though summer bottom temperature may also be critical. The distribution of standing stock biomass in relation to diversity suggests predation pressure on the southern and northern extremes of the study area, presumably the result of benthic-feeding marine mammal populations and possibly, in the case of the southern region, demersal fish. In general terms it appears to be a strongly detrital-based trophic system, with an elevated standing stock biomass observed in the Bering Strait and southern Chukchi Sea region, probably the combined result of high near-surface primary productivity distributions and current structure. The benthic fauna over this region appears to be dominated by boreal Pacific forms, probably also a result of the current structure, with high Arctic forms frequent only in the northern waters.