The collapse of eastern Bering Sea snow crab

The snow crab is an iconic species in the Bering Sea that supports an economically important fishery and undergoes extensive monitoring and management. Since 2018, more than 10 billion snow crab have disappeared from the eastern Bering Sea, and the population collapsed to historical lows in 2021. We link this collapse to a marine heatwave in the eastern Bering Sea during 2018 and 2019. Calculated caloric requirements, reduced spatial distribution, and observed body conditions suggest that starvation played a role in the collapse. The mortality event appears to be one of the largest reported losses of motile marine macrofauna to marine heatwaves globally. Marine heatwaves, a component of our impact on the Earth’s climate, can bring both expected and unexpected environmental change. Between 2018 and 2021, after a period of historically high crab abundance and a series of marine heatwaves, the population of snow crab in the Bering Sea declined by 10 billion. Szuwalksi et al . used survey data to model the potential drivers of the decline in this ecologically and commercially important species. They found that the temperature of the water was not above the species’ thermal limits, but it did increase their caloric needs considerably (see the Perspective by Kruse). This increase, in conjunction with a restriction in range, led to an unexpected mass starvation event. —SNV A marine heatwave precipitated the collapse of the eastern Bering Sea snow crab population.