Environmental effects on cephalopod community structure and distribution on the eastern Bering Sea upper continental slope.

The eastern Bering Sea upper continental slope (EBSS) is highly productive and abundant in fishery resources, and it is also a key sensitive area to climate change. Cephalopods are widely distributed in this region, but there is still a significant lack of research on their species in EBSS, especially in terms of the impact of climate driven changes in the marine environment on their spatiotemporal distribution. As a key component of the marine food web and a valuable fisheries resource, cephalopods are highly sensitive to environmental changes. Utilizing survey data from the Alaska Fisheries Science Center (AFSC), we investigated the community structure and spatial and temporal distributions of three cephalopod species on the EBSS, and the relationship between catch-per-unit-effort (CPUE) and depth, sea bottom temperature (SBT), and sea surface temperature (SST) using a generalized additive model (GAM). Furthermore, a habitat suitability index (HSI) model was used to evaluate the effects of regional environmental variations on the habitat distribution of dominant cephalopod species during marine heatwaves (MHWs). The results revealed a diverse cephalopod community on the EBSS comprising 20 species (3 orders, 9 families, and 15 genera) including 12 species of Teuthoidea, 7 species of Octopoda, and 1 species of Sepioidea. Depth had the greatest influence on the three dominant species (Berryteuthis magister, Enteroctopus dofleini, and Opisthoteuthis californiana), followed by SBT and SST. MHWs contributed to marine environmental changes, which, in turn, affected the CPUE of the dominant cephalopod species. Compared to the 2010 MHW, the anomalous warming of the seawater during 2016 caused a reduction in the suitable habitat distribution for B. magister, while increasing suitable habitats for E. dofleini and O. californiana, and thus, increasing cephalopod abundance.