Federal fisheries researchers studying the dramatic crash of snow crab in the Bering Sea from 2018 to 2021 have determined that caloric requirements of the crab quadrupled when sea temperatures rose and the crab ultimately starved to death.
Snow crabs will eat almost anything they can catch and break open with their claws, a diet that may include fish, shrimp, crabs, worms, clams, brittle starts, snails, algae and sponges, as well as anything dead they find.
In 2018, there were more snow crab in the Bering Sea than ever seen before, Cody Szuwalski, a fisheries biologist with the National Oceanic and Atmospheric Administration’s Alaska Fisheries Science Center, said.
So the decline of roughly 10 billion crab from 2018 to 2021 was a precipitous unexpected collapse, he said in a podcast interview by NOAA.
It wasn’t immediately clear what was going on, because those temperatures observed in the Bering Sea were not themselves lethal to crab.
The NOAA team first considered a range of possible causes for the rapid decline of the snow crab, ranging from cod predation, cannibalism and disease. Rising temperatures themselves were not lethal to the crab.
One of the most important studies they did took crab and put them in different temperatures of water and then measured how much they ate. The team was able to calculate the caloric requirements for the population over time, and they calculated that those caloric requirements quadrupled.
Those crab being in a more confined area of the Bering Sea, must have starved, they said.
The findings were reported in an April 25 podcast where Szuwalski was interviewed by John Sheehan, the host of “Dive In With NOAA Fisheries.”