The population of snow crabs in the Bering Sea has been declining for the last five years, but this season the population has completely collapsed.
There used to be billions of snow crabs in the Bering Sea. The crabs, however, have virtually disappeared from these waters due to a recent and severe population crash, and they could not be returning any time soon.
The Bering Sea was home to around five billion juvenile crabs and nearly three billion mature snow crabs (Chionoecetes opilio) in 2018, according to a Seattle Times story (opens in new tab). However, by the end of 2021, those figures had fallen to 2.5 million and 6.5 million, respectively, representing a decline of about 8 billion crabs in just three years. The Alaska Department of Fish and Game (ADFG) made the difficult choice to suspend the season’s snow crab harvest in early October out of concern that the crustaceans might go extinct entirely. In February, the National Marine Fishing Service issued an official overfishing notice(opens in new tab) for the population.
Given the state of the stock, management of Bering Sea snow crab must now prioritise conservation and rebuilding, according to a statement from ADFG representatives (opens in new tab). Due to insufficient survey numbers, the agency also decided to cancel the fall harvest of Bristol Bay red king crabs (Paralithodes camtschaticus).
The choice was “very challenging,” according to area management biologist Miranda Westphal of the Alaska Department of Fish and Game.
She told Live Science, “It was one of the hardest decisions we’ve ever had to make, and it came after a lot of sleepless nights and a lot of tears.”
What led to the crash of the snow crab? The Seattle Times observed that although unsustainable fishing methods may also have contributed, the primary offender was probably certainly human-caused climate change (opens in new tab).
In the chilly northern waters of the Bering Sea floor, snow crabs flourish. The temperature of the water is crucial to the life cycle of these crabs and not merely an issue of comfort. Seawater loses buoyancy and saltiness as it cools, sinking to the bottom of the ocean. According to the National Oceanic and Atmospheric Administration(opens in new tab) (NOAA), marine biologists refer to this chilly layer of water as the “cold pool.” While many fish and other marine life avoid the cold pool, young snow crabs find it to be a safe haven because there are almost no predators willing to enter its icy waters.
Record heat waves in 2016, 2018, and 2019 stunted the formation of cold pools in the Bering Sea, leaving young crabs vulnerable to predators, according to a NOAA report released on September 2(opens in new tab). In addition, Westphal said, the warmer waters likely sped up the adult crabs’ metabolism, causing them to starve. As anthropogenic climate change advances over the coming decades, these kinds of heatwaves are projected to become more frequent.
In the Bering Sea, trawling vessels targeting other marine species frequently encounter, catch, and discard unwanted snow crabs as “bycatch.” When snow crab fishers haul a catch aboard, they discard crabs that are deemed to be too small, too young, or whose shells are discoloured or marred in some way. These practises may have contributed to the sharp decline in crab numbers in addition to climate change.
In 2020, the ADFG estimated that over 30% of all snow crabs that were captured and tossed back into the Bering Sea died as a result, according to a report in the Seattle Times in April. NOAA’s 2021 assessment for Bering Sea snow crabs (opens in new tab) corroborated these sobering findings, with snow crab mortality increasing that year and populations plunging.
The cancellation of the crab season this year and the uncertain future of the snow crabs in the Bering Sea could have significant effects on the industry, which brought in about $280 million in 2016, according to the Anchorage Daily News(opens in new tab), as well as on the many local fishers who depend on snow crabs for their livelihoods.
KIMA-TV(opens in new tab), a television station in Yakima, Washington, quoted Jamie Goen, executive director for Alaska Bering Sea Crabbers, as saying that “people are just going to go bankrupt and they’re not going to be able to feed their family.”
According to KIMA-TV, Goen’s group is currently urging the North Pacific Fishery Management Council to enact better conservation measures to aid in the recovery of a sustainable snow crab population.
But for the time being, professional fishermen won’t be allowed to catch any crabs because “we want to give them the best chance to recuperate,” according to Westphal.