According to a NOAA study, the most likely cause for the mass disappearance was starvation caused by a marine heatwave between 2018 and 2019.
When scientists estimated that more than 10 billion snow crab had disappeared from the Eastern Bering Sea between 2018 and 2021, industry stakeholders and fisheries scientists had several ideas about where they’d gone.
Some thought bycatch, disease, cannibalism, or crab fishing, while others believed it could be predation from other sea animals like Pacific cod.
But now, scientists say they’ve distinguished the most likely cause for the disappearance. The culprit is a marine heatwave between 2018 and 2019, according to a new study authored by a group of scientists with the National Oceanic and Atmospheric Administration.
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More carbon dioxide in the atmosphere means warmer temperatures, Litzow said, which is bad news for the cold-loving snow crab. And more greenhouse gasses also mean more acidic oceans, which can also be dangerous for some crab.
“Carbon dioxide that we release through fossil fuels is also taken up by the oceans and has the effect of reducing the pH of the ocean — it makes it more acidic,” Litzow explained. “Because crab use calcium carbonate in their exoskeleton, they’re vulnerable to that acidification because calcium carbonate dissolves more and more easily as pH goes down.”
The good news — at least for snow crab — is they’re not as sensitive to ocean acidification as other species.
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Maggie Nelson, KYUK, 16 November 2023. More information.
