SEATTLE – Federal biologist Erin Fedewa boarded a research ship in Dutch Harbor in June and traveled to part of the Bering Sea that typically produces an abundance of young snow crabs in annual surveys.
Not this summer. At this point and elsewhere, the sampling nets found surprisingly few – a decline in immature females of more than 99% compared to those found just three years earlier.
Biologists also noted a significant decrease in the number of adult snow crabs when they carefully sorted the marine life they had brought in.
“The youth were obviously a red flag, but almost every size of snow crab has declined dramatically,” said Fedewa. “It’s very scary.”
This collapse in the Bering Sea snow crab population comes amid a decade of rapid climatic changes that have disrupted one of the world’s most productive marine ecosystems in ways that scientists are only just beginning to understand. The changes are forcing them to rethink how they are developing models to predict harvest times.
As the water warms, some older crabs have moved northwest, young crabs are being eaten by increased numbers of predators, and diseases are on the rise. All of this could make crabs more susceptible to overfishing, and this has increased concerns about the impact of trawlers who accidentally pick up crabs while pulling nets across the ocean floor and targeting bottom-dwelling fish.
The forecast for the 2022 winter snow crab season is bleak. It is reckoned to be well under Â£ 12 million at best. That would be less than a Â£ 45 million harvest in 2021 and a fraction of the more than Â£ 300 million taken in two peak years in the early 1990s.
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The iconic Bering Sea king crab, which can grow up to 24 pounds with a leg span of up to five feet, is also in trouble. A major blow to the commercial crabs, many of which are Washington-based, the October harvest for these crabs was canceled, which has only happened three times before.
According to Jamie Goen, executive director of Seattle-based Alaska Bering Sea Crabbers, overall conservation efforts are expected to wipe out most of the value of the Bering Sea crab harvest, which was worth more than $ 160 million last year .
“We’ve been hit twice, and the economic impact is unlike anything we’ve seen in this industry,” said Goen.
The decline in crops will also hit some communities in Alaska that rely on the crab fleets to sustain their economies. St. Paul, on the Pribilof Islands northwest of Dutch Harbor, is the location of a large shrimp processing facility operated by Trident Seafoods, based in Seattle, and relies on crabs to generate activity not only for its port, but around Pay taxes that prop the local government on.
Crabs want to do more to protect crabs from some types of fishing, including trawling.
Goen said crabs will urge fisheries managers to step up protective measures, such as:
“We need others” [fishing] Sectors to report and protect the crab, âsaid Goen.
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Both king and snow crabs are caught off Alaska using steel-framed pots that are set up along the ground by a fleet of around 60 ships. Each boat typically employs six to seven crew members, some of whom have appeared on the Discovery Channel’s longtime reality TV series “Deadliest Catch”.
Most of the king crab harvest and snow crab sold in the United States in recent years has been imported from other countries.
But the downturn in US stocks could drive consumer prices higher.
Less ice, warmer water
Marine conditions are key for scientists studying the Bering Sea crab decline, which is now the lowest total for any species in more than four decades.
“That’s huge,” said Bob Foy, director of the Alaska Fisheries Science Center for the National Oceanic and Atmospheric Administration. “It’s a massive change for our Bering Sea ecosystem, and the implications for other fisheries are just being considered.”
He notes that the snow crab pups were still on an upward trend two years ago. Then, within 48 months, they appeared to have imploded.
One research focus is the Bering Sea ice, which forms every winter and acts as a huge platform for algae to grow at the foot of the food chain. When it freezes, the ice sheds a thick layer of cold, salty seawater that eventually forms a cold pool on the bottom, ideal conditions for young snow crabs.
In the last few winters, the extent and thickness of the ice has decreased significantly.
During those weak ice years, the size of the cold pool has shrunk, a retreat that has been accurately captured by federal researchers.
One of the crab’s voracious predators – cod – doesn’t like the cool temperatures in the cool pool. The warmer temperatures seem to have enabled the cod to hunt much more young snow crabs, according to Fedewa, who said analysis of cod bellies shows they are eating more crabs.
“The assumption is that the thermal barriers in cold-water habitats that protected young snow crabs from predators like the Pacific cod are essentially breaking down,” said Fedewa.
King crabs can also suffer from increased predation.
Earlier federal research in the 1980s showed that young sockeye salmon from Bristol Bay like to feed on king crab larvae. There have been a number of tough sockeye runs in recent years, which could be at least partially due to warmer and more favorable conditions in the lakes where they rear up before transitioning into salt water.
âThat is a hypothesis that needs to be examined more closely,â said Fedewa.
Warming trends in the Bering Sea appear to be increasing the numbers of crabs found further north. The trends tracked by surveys are not fully understood.
The autumn Bering Sea king crab harvest was canceled due to the low number of adult females.
But this summer’s survey showed an increase in adult female king crabs in more northerly areas. These crabs were counted outside the main study zone and therefore not used to calculate potential harvests.
Snow crab populations also appear to be shifting.
This past winter, shrimp dump trucks reported an unusual harvest time when the main concentrations of snow crabs were found about 500 miles northwest of Dutch Harbor, which is about twice the typical distance for fishing in February and March.
âThe crabs we found were good crabs. They were just a lot farther away than we traditionally fish, âsaid Tom Suryan, who has been fishing for crabs for over 40 years and plans to retire.
Suryan, the captain of the Bristol Mariner, said he was about 60 miles from the sea border with Russia.
Other boats were even closer.
âI could literally spit across the Russian border. I mean, we were there – except for a quarter mile, âsaid Owen Kvinge, captain of the Seattle-based Arctic Sea, who suggests some of the US crabs have immigrated to Russian waters.
Although crab populations fluctuate, there are cautionary stories of Alaskan collapse that continue to haunt the industry.
In the 20th century, the Gulf of Alaska was the site of a large king crab fishery that boomed and then went bust. It closed in the early 1980s but has yet to be reopened.
The king crab fishery in the Bering Sea also has an eventful history. Annual catches rose to around 130 million pounds in the early 1980s, then crab stocks collapsed and the harvest ceased. Since 1996, after two consecutive years of closure, harvests have never exceeded Â£ 22 million and dropped to Â£ 2.6 million last year.
In a whistleblower complaint filed with NOAA Fisheries earlier this year, a former federal fisheries biologist based in Kodiak alleged that federal surveys were improperly conducted in the 1970s and 1980s, with extra hauls in random locations and other steps to get around the Estimates to purposely inflate crab populations.
Whistleblower Braxton Dew said the flawed surveys set the stage for the overfishing, which he identified as the main cause of the king crab collapse. “It was a steep breakdown and that’s because of all the wrong numbers that were used,” Dew claimed in a recent interview.
Foy, director of NOAA’s Alaska Fisheries Science Center, said testing methods had changed and improved since the period mentioned in Dew’s complaint, and that even then the results had been subject to reviews that provided reviews and counterweights.
Later this fall, the Alaska Department of Fish and Game is expected to decide whether the snow crab harvests (also known as Opilio) can continue in 2020, and is also responsible for setting small Bering Sea harvest levels for Bairdi crabs and golden king crabs.
In the years to come, the crabs hope that populations can recover if strict protective measures are taken quickly.
However, their livelihoods could find themselves in a dangerous future if global warming counteracts recreation.
“The environmental impact is enormous,” said Suryan. âPerhaps the Bering Sea crabs are an indicator species – the proverbial canary in the coal mine. I dont know. But things are changing, we can be sure of that. “