Billions of Snow Crabs Have Disappeared From Alaskan Waters
https://www.aljazeera.com/news/2022/10/17/c...lions-disappear



Scientists have been left perplexed after billions of crabs and crustaceans reportedly disappeared mysteriously in the Bering Sea off the US state of Alaska in the last several years.

Ben Daly, a researcher with the Alaska Department of Fish and Game (ADF&G), told US media outlet CNN the snow crab population shrank from about 8 billion in 2018 to 1 billion in 2021.

“Snow crab is by far the most abundant of all the Bering Sea crab species that is caught commercially,” Daly said. “So the shock and awe of many billions missing from the population is worth noting – and that includes all the females and babies.”

While the reasons for the dramatic fall in the crab population are still being researched, experts fear the likely cause includes increased predation and stresses from warming water on the cold-water species.

“Environmental conditions are changing rapidly,” Daly told CBS News. “We’ve seen warm conditions in the Bering Sea the last couple of years, and we’re seeing a response in a cold-adapted species, so it’s pretty obvious this is connected. It is a canary in a coal mine for other species that need cold water.”

The sharp drop in their numbers forced the ADF&G last week announced the cancellation of the Alaska snow crab harvest for the first time ever in Alaska, the United States’ largest state.

It said that while there would be “substantial impacts” on harvesters, the department has to balance the impacts with the “need for long-term conservation and sustainability of crab stocks”.

The authority also scrapped the Bristol Bay red king crab harvest.

Jamie Goen, executive director of the Alaska Bering Sea Crabbers said some crabbers will be going out of business as a result of the cancellation.

“This is so unbelievable that this is happening. We have third-generation fishermen who are going to go out of business,” AP news agency quoted Geon as saying.

Last year’s snow crab harvest of 2,540 tonnes was the smallest in more than 40 years. According to the Alaska Seafood Marketing Institute, the crab fishing industry in Alaska is worth approximately $200m.


This post has been edited by petpenyubobo: Mar 24 2023, 11:05 PM

Billions Gone: What’s Behind The Disappearance of Alaska Snow Crabs?
https://www.theguardian.com/environment/202...aska-snow-crabs



Just off Alaska’s coast, the east Bering Sea usually teems with snow crabs, their spindly legs scuttling across an almost frozen ocean realm. Those legs, prized by seafood lovers, underpin a crabbing industry in the state worth $160m (£143m) annually.

But this year, federal fisheries managers have closed the Alaska snow crab season for the first time, because of record population declines of more than 80% since 2018.

Beyond the unknown ecosystem effects of this loss, the closure has alarmed the fishers dependent on this industry, who will lose millions. Yet the Alaska Department of Fish and Game, which has imposed the limits, says that with the snow crab population in such a dire condition, they are left with no choice.

What can explain the decline? With so much at stake, scientists are investigating potential causes behind the crab collapse.

Origins of crisis
The first thing to understand is that it wasn’t a sudden decline, says Erin Fedewa, a fisheries research biologist for the National Oceanic and Atmospheric Administration (Noaa). “The snow crab story has to start back in 2018,” she says. That year, an unusually high snow crab population count coincided with one of the warmest years, and periods of lowest sea ice extent, on record in the Bering Sea.

This event – which was fallout from the north-east Pacific marine heatwave – was an anomaly attributable to the climate crisis, and associated with die-offs in a number of species including seals and seabirds.

In 2019 (another year of record-breaking temperatures), Noaa’s annual trawl survey in the east Bering Sea – designed to give fisheries managers and fishers an indication of the health of crab stocks – revealed steep declines in the numbers of juvenile crabs.

It is thought the warmer seas brought a unique challenge for these younglings, because they mature in cold-water pools on the ocean floor that are sustained by melting sea ice. Accelerated melting, coupled with warmer waters, likely shrunk the available habitat by pushing this chilled nursery above the 2C maximum that the juveniles need.

Why one got 3 pairs of legs the other got 4 pairs?

Aren't they from the same crustacean crab family?

One got duri (thorns) the other no duri?

More than 80% gone almost extinct already.