In 2018, the Bering Sea between Alaska and Russia was home to an enormous population of snow crabs. That year, surveys recorded exceptionally high numbers of the species. Then, within just a few years, the situation reversed.
More Than 10 Billion Snow Crabs Vanished
Between 2018 and 2021, more than 10 billion snow crabs disappeared from the eastern Bering Sea. By 2021, survey estimates had fallen to the lowest level recorded since the survey began in 1975.
At first, there was no simple explanation. Had fishing removed too many crabs? Had predators such as Pacific cod eaten them? Had the crabs migrated somewhere else? Was disease responsible?
According to NOAA Fisheries, scientists investigated these possibilities one by one. What they eventually found was much bigger than the disappearance of a single species. The sea itself was changing.
What Happened in the Bering Sea?
Snow crabs are adapted to cold water. In the Bering Sea, an important part of their habitat has historically been associated with the “cold pool,” a layer of cold bottom water shaped by winter sea ice. This cold environment supports snow crabs and other Arctic species.
But in 2018 and 2019, the Bering Sea experienced exceptionally warm conditions and a major marine heatwave. Sea ice declined, bottom-water temperatures increased, and the cold Arctic conditions that snow crabs had long depended on weakened.
According to NOAA Fisheries, the problem was not simply that the water became a little warmer. The conditions that made the Bering Sea suitable for snow crabs were changing.
The Crabs Did Not Simply Die From Heat
The evidence does not show that billions of snow crabs simply reached a lethal temperature and died from direct heat exposure. Something more complicated happened.
Warmer water increased their metabolism. As water temperature rises, snow crabs require more energy to maintain basic biological functions. Laboratory research cited by NOAA found that the caloric requirements of snow crabs nearly doubled as water temperatures increased from 0°C to 3°C.
According to NOAA Fisheries, a crab living in warmer water needed substantially more food just to survive. At the same time, the cold-water habitat available to the crabs was shrinking.
They Needed More Food — But Had Less Room to Find It
As the Bering Sea warmed, suitable cold-water habitat contracted. Large numbers of snow crabs became concentrated into a smaller area. Their energy requirements were rising while competition for food was becoming more intense.
Researchers also found evidence of declining body condition. Young crabs of similar size were lighter during the heatwave period than they had been before it.
Scientists investigated other possible explanations, including migration, fishing bycatch and predation. None was large enough to account for the disappearance of billions of crabs. The evidence increasingly pointed toward an energy crisis: the crabs needed more food in warmer water while shrinking habitat increased competition for what was available.
Starvation emerged as the most likely explanation for the extraordinary mortality. The warmer ocean did not simply cook the crabs. It disrupted the energy balance they needed to survive.
Then Billions of Snow Crabs Were Gone
In 2018, scientists had observed historically high numbers of snow crabs. By 2021, roughly 10 billion had disappeared. The commercial fishery collapsed with them.
According to NOAA, the fishery had been worth roughly $227 million before the collapse. Within two years, that value had fallen to zero.
Then came a decision without precedent. In October 2022, the Bering Sea snow crab season was canceled for the first time in U.S. history. The following season was canceled again.
This Was No Longer Just a Problem for Alaska’s Crab Fishermen
When the fishery stopped, the economic damage did not end with the boats. Fishermen lost income. Processors lost the crab they depended on. Distributors and seafood businesses were affected. Ports and fishing-dependent communities lost revenue.
A biological collapse beneath the surface of the Bering Sea had become an economic crisis. And soon, the state of Alaska turned to the federal government.
Alaska Asked Washington to Declare a Disaster
In 2022, Alaska requested a federal fishery disaster determination for crab fisheries affected by the collapse. In December 2022, the U.S. Department of Commerce approved fishery disaster determinations covering affected Alaska crab fisheries.
According to NOAA Fisheries, the collapse that began beneath the surface of the Bering Sea had now become an officially recognized federal fishery disaster.
The Federal Government Stepped In
Federal recognition was followed by financial assistance. For the 2021–2022 Alaska crab fishery disasters, the federal government allocated approximately $94.6 million. For the 2022–2023 Bering Sea snow crab and Bristol Bay red king crab disasters, approximately $96.7 million was allocated.
According to NOAA Fisheries, the crisis did not end there. The 2023–2024 Bering Sea snow crab fishery was also approved for federal fishery disaster assistance, with another $39.5 million allocated.
The Economic Shock of the Snow Crab Collapse
| Event | Scale | Why It Matters |
|---|---|---|
| Snow crabs lost | More than 10 billion | Decline occurred between 2018 and 2021 |
| Population decline | More than 90% | Abrupt collapse during the marine heatwave period |
| Fishery value | About $227 million → $0 | Collapse occurred within roughly two years |
| 2022 snow crab season | Canceled | First cancellation in U.S. history |
| Following season | Canceled again | Two consecutive closures |
| 2021–22 Alaska crab disaster funding | About $94.6 million | Federal disaster assistance |
| 2022–23 crab disaster funding | About $96.7 million | Federal disaster assistance |
| 2023–24 snow crab disaster funding | $39.5 million | Additional federal assistance |
The numbers tell a larger story. A major American fishery was shut down for the first time in its history. The state asked the federal government for help. The U.S. Department of Commerce formally recognized fishery disasters. Tens of millions of dollars in federal assistance were allocated repeatedly.
But What Happened to the Sea After the Crabs Disappeared?
Snow crabs are not simply seafood for humans. They are part of the Bering Sea food web. They consume organisms living on and near the seafloor, while young snow crabs are prey for fish including Pacific cod.
But it would be too simplistic to say that the disappearance of snow crabs caused the entire Bering Sea ecosystem to change. The evidence points to something larger. The ecosystem itself was already changing. The snow crab collapse was one of the most dramatic consequences of that transformation.
The Bering Sea Is Becoming a Different Sea
For decades, the Bering Sea has been strongly influenced by winter sea ice and cold Arctic conditions. But as sea ice declines and bottom temperatures rise, the structure of the ecosystem is changing.
Scientists call this process “borealization.” In simple terms, an ecosystem dominated by Arctic conditions is shifting toward a warmer, more sub-Arctic state.
NOAA researchers found evidence of a broad ecological transition involving sea ice, bottom temperatures, plankton and fish communities. Cold-adapted species are losing some of the environmental conditions that historically supported them, while species better suited to warmer waters gain opportunities to expand.
Climate Change Is Changing Who Can Live in the Sea
A 2024 study published in Nature Climate Change found that the strongly boreal conditions associated with the snow crab collapse are now roughly 200 times more likely than under the preindustrial climate. The researchers concluded that the rapid borealization of the Bering Sea was more than 98% likely to have been human-induced.
Climate change does more than raise the temperature of the ocean. It changes which species are best equipped to survive there. In that sense, climate change is changing who gets to live in the Bering Sea.
What Happens in the Ocean Does Not Stay in the Ocean
The collapse of Bering Sea snow crabs is not simply the story of one species. It shows how tightly the natural world and the human economy are connected.
The ocean warmed. The crabs needed more energy. Their cold-water habitat contracted. More than 10 billion snow crabs disappeared. A fishery worth hundreds of millions of dollars collapsed. For the first time in U.S. history, the Bering Sea snow crab season was canceled. Alaska requested federal disaster assistance. The U.S. government officially recognized fishery disasters.
The deepest scar left in the Bering Sea is not simply the empty space left by billions of missing crabs. It is the possibility that the Bering Sea itself is becoming something fundamentally different from the sea we once knew.
FAQ
Did more than 10 billion snow crabs really disappear?
Yes. NOAA researchers estimate that more than 10 billion snow crabs disappeared from the eastern Bering Sea between 2018 and 2021.
Did the crabs simply die because the water became too hot?
No. Warmer water increased their energy requirements while suitable cold-water habitat contracted. Researchers concluded that increased metabolic demand, shrinking habitat and insufficient food likely created severe energetic stress, with starvation playing a major role.
Could the missing crabs simply have migrated somewhere else?
Scientists investigated that possibility. Surveys did not find enough crabs farther north or elsewhere to account for the enormous decline. Movement, fishing bycatch and predation were insufficient to explain the disappearance of billions of crabs.
Did the U.S. government really declare it a disaster?
Yes. The U.S. Department of Commerce approved federal fishery disaster determinations covering affected Alaska crab fisheries in December 2022, and federal funding was subsequently allocated.
Was the snow crab season really canceled for the first time in U.S. history?
Yes. The 2022–2023 Bering Sea snow crab season was canceled for the first time in the history of the fishery. The following season was also canceled.
How strong is the connection to climate change?
A 2024 Nature Climate Change study found that the rapid borealization associated with the collapse was more than 98% likely to have been human-induced, and that strongly boreal conditions like those associated with the collapse are now roughly 200 times more likely than under preindustrial climate conditions.
Are the snow crabs coming back?
There have been signs of improvement, and the fishery eventually reopened after two consecutive closures. The latest survey provides much clearer evidence of recovery. According to NOAA Fisheries’ 2025 Bering Sea survey, estimated snow crab biomass on the eastern Bering Sea shelf increased by 52% from 2024 to 2025, while the population was estimated at 7.2 billion individuals. NOAA’s 2026 technical memorandum also reports that the recovery signs that began in 2023 continued in 2025 as large juvenile cohorts started reaching maturity. Even so, the recovery is not complete: recruitment into the smallest juvenile size classes remained limited, and the broader long-term shift toward warmer, more boreal conditions remains a major concern.
What is the most important lesson from the Bering Sea snow crab collapse?
Climate change should not be understood only as a change in average temperature. A few degrees of warming can change how much energy an animal needs, where it can live, food webs, fisheries and eventually human economies and disaster policy.