Alaska’s snow crab collapse is likely tied to climate change


Alaskan officials recently canceled the Bering Sea snow crab season for the first time ever after scientists discovered an unprecedented decline in crab numbers. Climate change is the No. 1 suspect in the dropoff.

“We’re still trying to figure it out, but certainly there’s very clear signs of the role of climate change in the collapse,” said Dr Michael Litzow, shellfish assessment programme manager at the National Oceanic and Atmospheric Administration (NOAA), which runs an annual survey of Bering Sea snow crab numbers. (Snow crabs are also found in the Beaufort and Chukchi seas off Alaska.)

The decision to cancel, announced by the Alaska Department of Fish and Game on Oct 10, came as a devastating blow for local fisheries in a state where the seafood industry is an economic cornerstone. Commercial landings last year of Alaska snow crab alone came to 44 million pounds (19,958 tonnes) and US$219 million (S$311 million), according to NOAA data.

The bad news did not end there. State officials also announced the cancellation of the Bristol Bay red king crab season for the second year in a row because of consistently low crab numbers.

The Alaskan commercial crabbing fleet “is bracing for half a billion dollars in losses going into the second year of stock collapse”, the Alaska Bering Sea Crabbers trade association said, in addition to more ripple-effect losses in revenue to processors, support businesses and communities. The trade association represents about 60 vessels and 350 fishermen.

The Alaskan crab crisis is complicated, in part because the situations for the two different crab populations are quite different. The Bering Sea snow crabs have declined by “multiple billions” over just a few years, according to Dr Litzow.

In 2021, there were just enough adult crabs to meet the regulatory threshold to keep the commercial crabbing season open. But with so few smaller crabs around, the outlook for 2022 was grim. This year’s survey only confirmed that, resulting in the closure of the snow crab season for the first time.

It was not entirely clear not what happened to all the snow crabs, but climate change is thought to be a big contributor.

The Bering Sea water temperatures were much warmer than average in 2018 and 2019, contributing to low sea-ice cover levels. Snow crabs are cold-water animals, explained Dr Litzow, and “they’re sensitive to the loss of sea ice and really warm temperatures”.

He said: “There are some signs of another wave of really small crabs coming into the survey, and so looking out four to five years from now, those crabs, if they survive, would be coming into the fishery. So that’s the bright news. But if you’re trying to pay off a boat loan or keep a team employed, five years is a really long time.”

State rules stipulate there have to be at least 8.4 million mature females for the red king crab season to go forward. But the mature female population was just below the threshold this year and last year, as well as a few other times over the past four decades, prompting season closures.

For now, Alaskan fisheries are in trouble and there is no immediate end in sight.




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