Benthic macrofaunal compositional variations in the northern Bering Sea

Abstract

Point sampling of soft-sediment macrofauna provided a regional-scale analysis of species composition, diversity, and demographic distributions in the northern Bering Sea (61°0′–65°30′N Lat) in spring 2006. Taxonomic differences distinguished subregions north and south of St. Lawrence Island (P < 0.1%). High compositional variability occurred within and between sites, with higher variability among northern sites. One to two species dominated most assemblages, with moderately common or rare species. Ampeliscid amphipods characterized the north, and bivalves the south. Bivalves (Macoma calcarea Gmelin, Nuculana radiata Krause, Ennucula tenuis Montagu) were commonly widespread, in varied abundances and sizes. Overall, the extensive soft-sediment habitat supports a varied fauna composition with location, in species dominance, abundance, and size-class. This spatially heterogeneous regional structure is important in assessing ecosystem performance related to secondary production, biogeochemistry, bioturbation, top predator feeding strategy, recruitment, and in measuring change.