The collapse of eastern Bering Sea snow crab

Area of Science:

• Marine Biology
• Ecosystem Dynamics
• Fisheries Science

Background:

• The Bering Sea snow crab (Chionoecetes opilio) is ecologically and economically vital.
• Significant population declines, reaching historical lows in 2021, have been observed since 2018.
• This species supports a major commercial fishery and is subject to extensive management.

Purpose of the Study:

• To investigate the causes behind the dramatic collapse of the eastern Bering Sea snow crab population.
• To determine the role of marine heatwaves in the observed snow crab mortality.
• To assess the potential impact of starvation on the population decline.

Main Methods:

• Linking population data with marine heatwave events in the eastern Bering Sea (2018-2019).
• Calculating snow crab caloric requirements under changing environmental conditions.
• Analyzing spatial distribution shifts and observed body condition indices.

Main Results:

• A severe marine heatwave occurred in the eastern Bering Sea in 2018 and 2019.
• Calculated caloric needs, reduced habitat availability, and poor body condition indicate starvation.
• The snow crab population collapse is linked to this marine heatwave event.

Conclusions:

• Marine heatwaves pose a significant threat to marine ecosystems and commercially important species.
• Starvation is identified as a key factor contributing to the snow crab population collapse.
• This event represents one of the largest documented losses of mobile marine macrofauna due to marine heatwaves globally.