Macroinfauna communities on the Bering Sea continental shelf

Benthic infauna are vital to ecosystem functioning and serve as key indicators of changes driven by anthropogenic and natural stressors. In the Arctic, monitoring infauna communities is integral to climate change research. However, despite its status as a major fishing ground significantly impacted by climate change, the subarctic US Bering Sea lacks a comparable monitoring effort. The last comprehensive infauna survey on the Bering Sea shelf occurred over 4 decades ago, in the late 1970s. To address this gap, we compiled infauna data from Bering Sea flatfish habitat studies (2006-2021), providing insights into recent community compositions and spatial distribution patterns. Here we describe the spatial distributions of total infauna and, separately, of the taxonomic groups Amphipoda, Bivalvia, and Polychaeta, as well as key polychaete families significant in classifying infauna communities. Two distinct communities were identified: one in the subarctic northern shelf, including Norton Sound, and another in the boreal southern shelf, extending along the Alaska Peninsula into Bristol Bay. Community classification remained consistent whether based on all infauna families or restricted to polychaete families. This study reveals that general patterns of infauna distribution and biomass hotspots observed in the 1970s have persisted to the present, including high biomass of infauna on the southern middle shelf, Oweniidae polychaetes on the northern inner shelf, and amphipods and bivalves on the northern outer shelf. The persistence of these patterns suggests that key environmental factors influencing infauna community structure, particularly those proxied by depth and substrate type, have remained relatively stable on the Bering Sea shelf.