In recent years, the oceanic expanse around Alaska has reported a distressing disappearance of billions of snow crabs, and now, scientists have finally uncovered the culprit responsible: rising ocean temperatures that led to mass starvation among the crustacean population.
This alarming revelation emerges in the wake of the announcement from the Alaska Department of Fish and Game regarding the cancellation of the snow crab harvest season for the second consecutive year. The decision was prompted by the startling paucity of crabs inhabiting the traditionally freezing and perilous waters of the Bering Sea.
A study conducted and released by the National Oceanic and Atmospheric Administration discovered a significant correlation between marine heatwaves occurring in the eastern Bering Sea and the sudden vanishing of snow crabs, as observed from data collected in 2021.
Cody Szuwalski, the study’s principal contributor and a fishery biologist at NOAA, admitted his shock upon receiving the data. The dearth of crabs in the survey gave rise to hopes that it was merely a discrepancy in data collection, but the bleak reality struck in 2022, firmly indicating a challenging road ahead.
Interestingly, overfishing, which was initially considered a contributor to the dwindling snow crab population, was ruled out as it didn’t effectively explain the collapse. The exhaustive research divided the causes of the crab population’s decline into two broad categories: relocation or death. The data suggests that the primary factor behind crab death was food scarcity induced by warmer ocean temperatures which dramatically increased their metabolism and caloric requirement.
Predominantly a cold-water species, snow crabs are found thriving in areas with water temperatures below 2 degrees Celsius. However, they can adapt to waters up to 12 degrees Celsius. From 2018, warmer oceanic waters disturbed the crab’s metabolism and amplified their caloric demand by almost four times than previous years. This, coupled with the heat-induced disruption of the Bering Sea’s food web and the invasive presence of the Pacific cod, rendered the crabs incapable of meeting their caloric needs.
The dissipation of sea ice, particularly around Alaska’s Bering Sea, as a direct result of climate change has intensified global warming. In 2018 and 2019, the Bering Sea reported record-low ice coverage, providing a bleak forecast for the future.
The tragic fate of Alaska’s crabs underscores the rapid acceleration of the climate crisis and its increasingly consequential impacts on biodiversity and livelihoods. Szuwalski envisages long-term expectations for the snow crab population to migrate northwards as the ice recedes and in the eastern Bering Sea, the numbers of these hardy creatures might dwindle drastically.