A fishing tender with 65,000 pounds of Bristol Bay red king crab arrives at Peter Pan in King Cove for processing in 2011. Photo by Margaret Bauman for The Cordova Times.
Ocean acidification appears to be a driver in the decline of Bristol Bay red king crab, a highly value wild Alaska seafood that has for years been threatened by climate change.
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A new report published on Feb. 7 in the Canadian Journal of Fisheries and Aquatic Science said that negative effects of acidification explained 21% of recruitment variability of Bristol Bay red king crab between 1980 and 2023, and 45% since 2000.
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“Anthropogenic emissions of carbon dioxide into the atmosphere have generated a substantial increase in ocean carbon uptake and a shift in the marine carbonate system to a state of higher acidity and lower carbonate saturation states in a process referred to as ocean acidification,” the report said. “Carbon dioxide is more soluble in cold water, and high-latitude waters that are naturally cold and carbon-rich, such as the Bering Sea, are particularly vulnerable to acidification.”
According to Darcy Dugan, director of the Alaska Ocean Acidification Network, these findings mark a shift in messaging from the research community.
“Prior to the study researchers believed species in Alaska were likely being impacted but we didn’t have the data or analysis to back it up,” she said. “Red king crab is the first species where we can see a correlation between acidity and the decline of a wild stock.”
As head of NOAA’s Kodiak lab about a decade ago, Bob Foy – now science and research director of the Alaska Fisheries Science Center – said that if given enough time, Bristol Bay red king crab were likely to adapt to changing ocean conditions, but did not speculate on just how much time they would need.
The study led by Litzow and his colleagues noted that the study shows a correlation, and that it’s very difficult to prove direct causation because ecosystems are complex. The next steps to substantiate the findings are threefold. Studies are needed to improve validation of the Bering Sea ocean acidification model. Further studies are needed to identify where in Bristol Bay the juvenile red king crab are and to see if the pH is dropping down below threshold levels in areas they are occupying, and to better quantify the response of juveniles to pH.
The pH is a scale that measures how acidic or alkaline a substance is. pH is measured on a scale of 0 to 14. On this scale, a pH value of 7 is neutral, which means it is neither acidic nor basic. A pH value of less than 7 means it is more acidic, and a pH value of more than 7 means it is more basic.
Current monitoring and experiments ongoing at the Alaska Fisheries Science Center in Kodiak are aimed at addressing these questions.
Margaret Bauman, The Cordova Times, 26 February 2025. Press release.
