The Bering Sea is a vast marine ecosystem that has long supported one of Alaska’s most lucrative fisheries. Generations of fishermen have relied on these waters for their livelihood, establishing a deep economic and social structure around the annual harvest of prized shellfish. However, recent scientific surveys revealed a sudden, massive collapse in the populations of several commercially valuable crab species. The disappearance of billions of crabs from the ocean floor has delivered a profound shock to the Alaskan economy and signaled a dramatic ecological shift in the region.
Which Crab Species Disappeared and When
The crisis centered primarily on two commercially important shellfish: the Snow Crab (Chionoecetes opilio) and the Bristol Bay Red King Crab (Paralithodes camtschaticus). Scientific bottom-trawl surveys began registering alarming drops in abundance around 2018, with catastrophic declines manifesting in the 2021 and 2022 data. The Snow Crab population in the eastern Bering Sea suffered the most severe loss, with estimates indicating that over 10 billion individuals vanished between 2018 and 2021, representing a crash of over 90%.
Following these grim survey results, the Alaska Department of Fish and Game (ADF&G) canceled the Snow Crab fishing season in October 2022. This marked the first time in the fishery’s history that the season was completely closed, a measure taken to protect the remaining stock.
The Red King Crab fishery, concentrated in Bristol Bay, faced a parallel collapse. Its season was closed for the 2021/2022 period due to low population numbers and was canceled for a second consecutive year in 2022/2023. This dual closure of two of the region’s most valuable fisheries underscored the widespread ecological disaster impacting the Bering Sea’s bottom resources.
Leading Scientific Theories for the Decline
The leading scientific explanation for the mass mortality event points directly to the prolonged 2018-2019 marine heatwave that swept through the eastern Bering Sea. Snow Crabs are a cold-adapted species that rely on a region of cold bottom water, known as the “cold pool,” to regulate their metabolism and avoid predators. When the heatwave caused bottom temperatures to rise significantly, it triggered a physiological change in the crab population.
The elevated water temperature increased the crabs’ metabolic rates. Laboratory research indicated that the crabs’ caloric requirements nearly doubled under these warmer conditions. This meant the crabs needed to consume significantly more food just to maintain basic biological functions, including growth and reproduction.
This increased caloric demand occurred simultaneously with a reduction in the crabs’ available habitat, as the critical cold pool shrank, concentrating the population into smaller areas. The combination of high food requirements and increased competition for limited resources led to a widespread starvation event. Scientific models and observed body conditions of the remaining crabs support the conclusion that mass starvation was the immediate cause of the population collapse.
Scientists also considered secondary factors, such as increased predation pressure from species like Pacific cod, which moved north into the Bering Sea’s warmer waters. Localized disease outbreaks were also possible, as warmer temperatures can intensify a crab’s vulnerability to pathogens. Ultimately, the overwhelming evidence links the primary cause to the environmental shift, known as “borealization.” This process transitions the ecosystem from Arctic to sub-Arctic conditions, favoring warm-adapted species over cold-adapted ones, driven by warming ocean temperatures.
Regulatory Actions Taken
The immediate response to the scientific findings was a series of strict conservation measures. The Alaska Department of Fish and Game (ADF&G), in cooperation with NOAA Fisheries and the North Pacific Fishery Management Council (NPFMC), canceled the directed fishing seasons. The closure of the 2022/2023 seasons for both Snow Crab and Bristol Bay Red King Crab was designed to protect the minimal remaining reproductive biomass.
Regulators also faced pressure to address bycatch, the unintentional capture of crab in other fisheries. Crab industry groups petitioned for emergency closures of specific areas, such as the Red King Crab Savings Area, to all fishing gear, including that used by the pollock trawl fleet. They argued that reducing incidental mortality was necessary for the depleted stocks to recover.
NOAA Fisheries denied the request for an emergency closure of the area to all gear types, citing a lack of evidence that the proposed regulations would significantly address the low abundance of mature female Red King Crab. However, regulatory bodies initiated a process to explore longer-term management measures aimed at reducing crab mortality from groundfish fishing. The federal government later declared a fisheries disaster for the affected seasons, which unlocked financial assistance for the industry.
Impact on Fishing Communities and the Industry
The cancellation of the two most valuable crab seasons delivered a severe economic blow to the Alaskan fishing industry and dependent communities. The total revenue loss, measured by the ex-vessel value paid to fishermen for the 2022/2023 closures, was estimated to be over $200 million. When factoring in the ripple effect on processors, suppliers, and support services, the total economic damage was projected to approach $500 million.
The social fallout was particularly acute in remote coastal towns like St. Paul Island, a largely Aleut community highly dependent on the crab fishery and its processing infrastructure. In an average year, the city collects significant revenue from fisheries taxes, but the season closure resulted in an anticipated loss of nearly 90% of that tax base. This financial shortfall immediately threatened the community’s ability to fund essential municipal services, including public safety and emergency medical services.
Generational fishing families, who have invested heavily in vessels and quota shares, faced financial ruin without the income from the annual crab harvest. To mitigate hardship, the Department of Commerce provided disaster relief funding. NOAA Fisheries also implemented regulatory flexibility, such as granting exemptions from regional delivery requirements to cope with processing plant closures. The crisis has forced these communities to confront the profound instability resulting from a sudden, climate-driven ecological collapse.