Why billions of snow crabs have disappeared in Alaska

(CNN) — Snow crab fishing in Alaska was canceled for the first time after billions of the crustaceans disappeared from the cold and treacherous waters of the Bering Sea in recent years.

The Alaska Board of Fisheries and the North Pacific Fishery Management Council announced last week that the snow crab population in the Bering Sea fell below the regulatory threshold to open the fishery.

But the actual numbers supporting that decision are staggering: The snow crab population has shrunk from about 8 billion in 2018 to 1 billion in 2021, according to Benjamin Daly, a researcher with the Alaska Department of Fish and Game.

“The snow crab is by far the most abundant of all commercially caught Bering Sea crab species,” Daly told CNN. “So the shock of many billions of the population disappearing is noteworthy, and that includes all the females and calves.”

The Bristol Bay red crab fishery will also be closed for the second year in a row, the agencies announced.

Officials cited overfishing as a reason for canceling seasons. Mark Stichert, fish and shellfish fisheries management coordinator for the state Department of Fish and Game, said more crabs were being caught than could be replenished naturally.

“So there were more removals from the population than inputs,” Stichert explained at Thursday’s meeting.

Between studies conducted in 2021 and 2022, he said, mature male snow crabs are down about 40%, with an estimated 45 million pounds remaining in the entire Bering Sea.

“It’s a scary number, to be clear,” Stichert said.

But calling the Bering Sea crab population “overfished” — a technical definition that triggers conservation action — says nothing about what caused its collapse.

“We call it overfishing because of the size level,” Michael Litzow, director of NOAA Fisheries’ Kodiak Laboratory, told CNN. “But it wasn’t overfishing that caused the collapse, that’s clear.”

Litzow says that man-made climate change is a major factor in the crabs’ alarming demise.

Snow crabs are cold-water species and are mostly found in areas where the water temperature is below 2 degrees Celsius, says Litzow. As the oceans warm and sea ice disappears, the ocean around Alaska becomes inhospitable to the species.

“There have been a number of attribution studies that have looked at specific temperatures in the Bering Sea or Bering Sea ice cover in 2018, and those attribution studies have concluded that those temperatures and low-ice conditions in the Bering Sea are a consequence of global warming,” Litzow said.

Temperatures around the Arctic have warmed four times faster than the rest of the planet, according to scientists. Climate change has caused a rapid loss of sea ice in the Arctic region, especially in Alaska’s Bering Sea, which in turn has amplified global warming.

“Closing fisheries due to low abundance and continuing research are the main efforts to restore populations at this time,” Ethan Nichols, assistant area management biologist with the Alaska Department of Fish and Game, told CNN. .

Stichert also said there might be some “optimism for the future” as a few juvenile snow crabs are starting to show up in the system. But it could be at least three or four more years before they reach maturity and help the population recover.

“It’s a ray of optimism,” Litzow said. “It’s better than not seeing them, for sure. Every year we get a little bit warmer and that variability is higher in Arctic ecosystems and high latitude ecosystems, so if we can get a colder period that would be good news for the crab.” of the snows”.

CNN’s Paradise Afshar and Sara Turnbull contributed to this article.

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