A marine heat wave occurred in the eastern Bering Sea during 2018 and 2019.  Since then, ten billion snow crab have vanished from the region and the fishery was declared overfished in 2021 and subsequently closed in 2022.  Over the last three decades, the geographic range of snow crab (Chionoecetes opilio) in the eastern Bering Sea has contracted to the north in association with warming near-bottom temperatures and reduction of the cold pool, a < 2 ^oC body of bottom water that forms in the spring during sea ice melt.  During years of extensive sea ice formation, the cold pool extends to the southeastern middle shelf (~56^oN), while during years of low sea ice formation, the cold pool contracts to the northwest (~60^oN).  In recent heat wave years, the cold pool was completely absent from the eastern Bering Sea shelf.  The causal mechanisms that link declining Bering Sea snow crab populations to shrinking cold pool extent are not fully understood, but include increased predation, higher levels of disease, direct thermal stress, and changes in food quantity and quality.  Here we present data that support reduced nutritional condition in large juvenile snow crab (prior to their terminal molt) collected in the southeastern Bering Sea during the 2019 heatwave.  We compare region-specific (southeastern and northern Bering Sea) crab condition in the 2019 heatwave year to two subsequent years (2021 and 2022).  Specifically, we have used moisture content and fatty acid concentrations in crab hepatopancreas tissue as a new and rapid condition metric.  Finally, we present specific fatty acid trophic markers that link decreasing crab energetic condition in southern regions during 2019 to a higher level of carnivory (18:1n-9/18:1n-7) and a decrease in diatom-sourced fatty acids (16:1n-7/16:0) fluxing to the benthos.     

Primary Presenter: Louise Copeman, National Oceanic and Atmospheric Administration (louise.copeman@noaa.gov)

Authors:

Louise Copeman, National Oceanic and Atmospheric Administration  (Louise.Copeman@noaa.gov)

Erin Fedewa, National Oceanic and Atmospheric Administration  (Erin.Fedewa@noaa.gov)

Michelle Stowell, Oregon State University  (Michelle.Stowell@noaa.gov)

Samantha Mundorff, Oregon State University  (Samantha.Mundorff@noaa.gov)

Jens Nielsen, Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington  (jens.nielsen@noaa.gov)