Science

referred to as hot water

Climate change After state takes unprecedented move, experts say a prime suspect in mass death of Alaskan snow crabs canceling your harvest this season to save the species.

According to an annual survey of the Bering Sea floor conducted by the National Oceanic and Atmospheric Administration, the total number of crustaceans fell to about 1.9 billion in 2022, from 11.7 billion in 2018, or a decrease of about 84 percent.

For the first time ever, the Alaska Department of Fish and Game announced that the Bering Sea snow crab season will be closed for 2022-23, saying in a statement that efforts should turn to “conservation and reconstruction given stock conditions”. . The state’s fisheries produce 60% of the country’s seafood.

The species is also found northward into the Chukchi and Beaufort Seas, but they do not grow to the size of a fish there.

Erin Fedeva, a marine biologist at the Alaska Fisheries Science Center, told AFP the staggering numbers seen today are the result of heatwaves in 2018 and 2019.

“The cold water habitat they needed was virtually absent, which suggests that temperature is actually the major culprit in this population decline,” she said.

According to the National Oceanic and Atmospheric Administration, Alaska is the fastest-warming state in the country, and is losing billions of tons of ice each year—critical for crabs that need cold water to survive.

“The environmental situation is changing rapidly,” said Ben Daly, a researcher at ADF&G. told CBS News, “We’ve seen warmer conditions in the Bering Sea over the years, and we’re seeing a response in cold adapted species, so it’s pretty clear that it’s linked. It’s a canary in a coal mine for other species that Cold water is needed.”

Historically abundant resources in the Bering Sea, their loss has been considered a bellwether of ecological disruption.

There are a number of ways in which warmer temperatures are believed to have eliminated the species.

Studies have shown that as temperatures rise, there is a greater prevalence of bitter crab disease, pointing to a greater prevalence of this disease.

Crustaceans, named for their love of cold water, are also under greater metabolic stress in warmer waters, meaning they require more energy to survive.

“A working hypothesis right now is that as the crabs starved, they couldn’t meet the metabolic demands,” Fedeva said.

Young snow crabs in particular require low temperatures to hide from their major predator, the Pacific cod, and temperatures in areas where juveniles usually live have ranged from 1.5 °C in 2017 to 3.5 °C (35 °C) in 2018. Fahrenheit to 38 degrees Fahrenheit) – with studies indicating 3C may be a significant threshold.

More research is underway and the findings should be published soon, but in the meantime, “everything really points to climate change,” Fedeva said.

“These are truly unprecedented and disturbing times for Alaska’s iconic crab fishery and for hard-working fishermen and communities,” Jamie Goen, executive director of Alaska Bering Sea Crabbers, said in a statement. Second- and third-generation crab-fishing families will “go out of business.”

The industry was also affected by the cancellation of Bristol Bay Red King Crab Fishing for the second year in a row.

Fedwa also noted that snow crab populations are not a major factor in the decline.

Fishing only removes large adult males, she said, “and we have seen these declines in snow crab of all sizes, which really suggest that some bottom-up environmental driver is at play.”

According to NOAA, male Alaskan snow crabs can reach six inches (15 cm) in shell width, but females rarely exceed three inches.

In some good news, this year’s survey showed a significant increase in immature crabs compared to last year – but it will take four or five years for the males of them to grow to fishable size.

After years of heatwaves, temperatures have returned to normal, and “hopefully leaving the crabs untouched will allow them to breed, there will be no deaths, and we can try to recover the stock,” Fedeva said. .

Gabriel Prout, whose Kodiak Island fishing business relies heavily on snow crab populations, told CBS News that a relief program is needed for fishermen, similar to programs for farmers who suffer crop failure. experience, or communities affected by storms or floods.

Asked what fishermen can do in this situation with their livelihood dependent on the sea, Prout replied, “Hope and pray. I think that’s the best way to say it.”

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