When scientists realized that nearly 10 billion snow crabs had gone missing from Bering Sea between 2018 to 2021, they weren’t sure where they could have gone. After searching for a potentially migrating population, however, they came to a much more unfortunate conclusion.
A new study published by National Oceanic and Atmospheric Administration (NOAA) researchers in Science found that the billions of snow crabs weren’t finding a new home—they were suffering from what was likely the largest mortality collapse known to the species. Researchers have been aware of the crabs’ disappearance for a while, but the extent of the catastrophe and the exact causes behind it were previously unknown.
“When I received the 2021 data from the survey for the first time, my mind was just blown,” Cody Szuwalski, lead author of the study and fishery biologist at NOAA, told CNN. “Everybody was just kind of hoping and praying that that was an error in the survey and that next year you would see more crabs. And then in 2022, it was more of a resignation that this is going to be a long road.”...
...Kerim Aydin, study co-author and fisheries research biologist with NOAA, says that a two-year marine heat wave that kicked off in 2018 sparked a two-pronged attack on the snow crabs. Not only did the warmer temperature push the crab’s caloric needs higher—the crabs sometimes needed as much as four times their normal caloric intake to survive—but it also drew other fish into the water to feed on the crabs’ food supply. The warmer water even invited in species like the Pacific cod that prey on the snow crab.
“This was a huge heat wave effect,” Aydin says, according to CNN. “When the heat wave came through, it just created a huge amount of starvation....
... the conditions that caused this catastrophic population collapse are only becoming more common due to climate change. “Climate change is the next existential crisis for fisheries,” the authors wrote in their study, “and snow crab are a prime example for how quickly the outlook can change for a population.”
