Increasingly acidic seas are killing the larvae of shellfish such as oysters, clams and scallops, driving down populations and driving up prices. And for that you have global warming to thank, according to a new study by a team of marine scientists.
As climate-boosting greenhouse gases are released into Earth’s atmosphere, the oceans absorb more carbon dioxide. This creates a chemical reaction that makes seawater more acidic, especially in colder regions of the planet. That means traditional fishing communities in New England, the Pacific Northwest and Alaska could take a huge hit.
The study’s authors, who reviewed data from multiple fields and published their findings in the journal Nature Climate Change, found that rising acidity has already cost the Oregon and Washington shellfish industries $110 million and threatened 3,200 jobs. And those numbers are only going to get worse in the coming decades, according to lead author Julia Ekstrom, director of the climate adaptation program at UC Davis.
Ekstrom told Discovery News: “We looked at all the coasts around the United States. There are more places vulnerable than we previously thought.”
The first marine ecosystems and shellfish to take the hit from rising global seawater acidification will be around the Pacific Northwest and Southern Alaska, followed by the north-central West Coast and the Gulf of Maine, according to the report, which states that the most vulnerable areas will feel the effects by 2030.
“SoCal isn't really expected to get hit hard directly with pH problems for a few decades, but the hypoxia [low-oxygen] problem associated with it could really devastate bottom fisheries,” says Zack Gold, who studied mollusks as a marine biology research assistant at Stanford University. On the other hand, that low-oxygen environment “could also potentially help squid fisheries, which do better in hypoxic environments," Gold says.
“We don’t have a major acidification problem in Southern California,” according to Gold's father, Mark Gold, acting director of the Institute of the Environment and Sustainability, director of UCLA's Coastal Center and former longtime president of Heal the Bay (he's also the brother of L.A. Times food critic Jonathan Gold, who previously was the Weekly's critic). “Also, our shellfisheries aren’t major. We have mussels. They are doing fine. Oysters in the Pacific Northwest are really what has been nailed to date.”
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Shellfish larvae are the most at risk because they do not have the protective shell that can shield them from acidic waters. Some shellfish species can handle acidic ocean waters better than others. Fishing communities may be forced to switch to harvesting those varieties, or to build more on-shore nurseries.
“UCLA and UW are doing predictive modeling for the West Coast of the U.S.,” Mark Gold says. “They are running various different climate scenarios, and if funded, they will look at impacts to pterodpods and variation in coastal pollutant sources like sewage treatment plants and rivers. We do not have a good prediction yet on when central and Southern California shellfish will be impacted by ocean acidification.”