At the end of August, I wrote a diary on an unprecedented die-off of Alaskan snow crabs in the Bering Sea and, for the second year in a row, the king crabs in Bristol Bay. Today's diary is an update to that peculiar story.
The culprit for the die-off, which occurred right before the 2022 and 2023 crab seasons open, has forced the Alaskan state government to close the Bering Sea and Bristol bay to crabbing. Erin Fedewa, a marine biologist with Alaskas' Fisheries Science Center, told the AP that oceanic heat waves in 2018 and 2019 were the culprit. Cold water was simply absent after a promising snow crab baby boom. The Arctic is warming at least four times faster than the rest of the world.
NOAA's Arctic Program in 2020 found a marked decrease in sea ice extent; snow crabs require ice-cold water for their food sources to thrive and crabs' to feed. As scavengers, crabs eat bivalves, brittle stars, crustaceans, worms, and other sea-bottom organisms.
In 2019, NOAA found record-breaking ocean temperatures in the southern portion of the Bering shelf, while the northern Bering shelf had temperatures that exceeded a whopping 7.2 degrees Fahrenheit in 2018. The Arctic Report further found that the loss of sea ice combined with the warming temperatures impacted the Bering Sea ecosystem so much that it even forced the migration of fish poleward.
"Environmental conditions are changing rapidly," Ben Daly, a researcher with ADF&G, 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."
Historically an abundant resource in the Bering Sea, their loss is considered a bellwether of ecological disruption.
There are thought to be several ways that warmer temperatures have depleted the species.
Studies have pointed toward a higher prevalence of Bitter Crab Disease as the temperature heats up.
The crustaceans, named for their love of cold water, are also under greater metabolic stress in warmer waters, meaning they need more energy to stay alive.
"A working hypothesis right now is that the crabs starved, they couldn't keep up with metabolic demands," said Fedewa.
Young snow crabs in particular need low temperatures to hide out from their major predator, Pacific cod, and temperatures in regions where juveniles typically reside jumped from 1.5 degrees Celsius in 2017 to 3.5 Celsius in 2018 (35 degrees Fahrenheit to 38 degrees Fahrenheit) — with studies indicating 3C might be an important threshold.
Intrafish.com writes on the King Crab disaster in Bristol Bay.
Some of the world's most important crab fisheries will be closed for the second consecutive season, including Alaska's lucrative Bristol Bay red king crab fishery.
The Alaska Department of Fish & Game and the National Marine Fisheries Service (NMFS) announced Sunday it would cancel red king crab fishing seasons in Bristol Bay and the Saint Matthew Island districts, as well as blue king crab fishing in the Pribilof and Saint Matthew Island districts.
The Bristol Bay red king crab total allowable catch (TAC) has been steadily declining over the past decade as regulators reacted to declining biomass levels.
A decade ago, regulators set the TAC at 6,730 metric tons, or just under 14.8 million pounds. But by the 2017-2018 season that had slid to around half that level.
The Alaska king crab harvest is one of the most lucrative fisheries in the United States. Last year's closure resulted in an estimated loss of over $200 million (€181.6 million) worth of harvests, Alaska Bering Sea Crabbers Executive Director Jamie Goen told IntraFish.
The ban devastates fishing fleets from Oregon, Washington, and Alaska. Many fishermen will go out of business as a result.
Essentially, king crabs will not be available to consumers as there is a ban on imports from Russia due to their war crimes in Ukraine and, most importantly, a shortage of female crabs; which is a dire indicator for the health of the population which has been in a steady decline for over a decade per the AP. Overfishing is not a cause of the population crash of female crabs; only the males are harvested. There is something wrong with the ecosystem from the sea bed moving upwards through the water column.
It is worth noting that king crab hatchlings survived the summer in Bristol Bay. If cold temperatures continue in 2021 and 2022, the male crabs will reach a fishable size in the next few years. Additionally, the crabs in the Chukchi Sea and the Beaufort Sea do have large populations of crabs. However, they are too small for fishing, and crabbers do not enter those waters.