Fishing season is canceled as snow crabs vanishing in heat
Rewind, for just a second, to 2018 and imagine a series of nets trawling the depths of the east Bering Sea.
Most every year, scientists with the National Oceanic and Atmospheric Administration look for snow crabs. They drop nets for half an hour across 400 different spots in the sea. They haul in and weigh their catch and then calculate a rough number of snow crabs in the area.
For that particular year, those scientists estimated 11 billion crabs were living, crawling, eating and reproducing in the frigid waters below, said Cody Szuwalski, a fishery biologist at NOAA. They had never seen such high numbers.
But by 2021, more than 90% of them would vanish.
That year's survey showed only about 1 billion crabs remaining. If the crustaceans were few, so were the theories. “Were they overfished?” Szuwalski asked, considering the options. Did they die of disease? Were they eaten? Did they eat each other?
“It was a very precipitous drop,” he said.
Szuwalski and a few other NOAA scientists set out to find an answer and last week published a report indicating that marine heat waves collapsed
the snow crab population.
Those findings fit into a long line of data points showing the devastating effects of climate change caused by humans burning fossil fuels. Greenhouse gases are warming the earth, and as ocean waters absorb that heat, marine temperatures also rise.
Remaining crab populations will take years to rebound, Szuwalski said. That spells pain for fishing fleets who suffered a first-ever canceled snow crab season in 2022-2023. Officials in Alaska decided earlier this month to cancel yet another snow crab season.
These swings are likely the new normal, scientists and wildlife experts say because marine heat waves are predicted to become more common and severe as climate change worsens.
“There are going to be winners and losers with climate change,” Szuwalski said.
Whether those winners are species that humans like to eat remains to be seen, he said.
While the ocean captures about a third of the planet's greenhouse gas emissions, it also absorbs about 90% of its heat, and over the past half-century, marine heat waves have been increasingly common.
Snow crab numbers will likely take between three and four years to recover, Szuwalski said.
Officials in Alaska won't decide until late next year whether to open the 20242025 snow crab season, and even if they do, harvests will likely be modest.
Climate change is making for unpredictable conditions.