September 23, 2016 — Millions of pounds of Dungeness crab are pulled from Pacific Northwest waters each year in a more than century-old ritual for commercial and recreational fishermen.
But as marine waters absorb more carbon dioxide in the atmosphere, federal scientists are worried that the ocean’s changing chemistry may threaten the sweet-flavored crustaceans.
So scientists with the NOAA Fisheries’ Northwest Fisheries Science Center are exposing tiny crab larvae to acidic seawater in laboratory experiments to understand how ocean acidification might affect one of the West Coast’s most lucrative fisheries.
Research published this year found that Dungeness crab eggs and larvae collected from Puget Sound and exposed to higher levels of carbon dioxide — which increases ocean acidity — grew more slowly and larvae were more likely to die than those in less corrosive seawater.
Now, researchers are taking the experiments a step further to study how the crabs respond to multiple stressors during various growth stages. They also plan to analyze the sublethal effects: Even if the crabs don’t die, are they affected in physiological or other ways by ocean acidification?
“They’re so economically and ecologically important here on the West Coast,” said Paul McElhany, a research ecologist with the Northwest Fisheries Science Center north of Seattle, who is leading the current experiments.
Crab larvae are valuable food for small salmon and forage fish like herring that are eaten by salmon. Dungeness crabs are also the top revenue-fetching fishery in Washington and Oregon. In 2014, nearly $200 million worth of crabs were harvested along the West Coast.