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In California, the native Olympia oyster — nearly wiped out by over-harvesting at the beginning of the 1900s — and the widely farmed Pacific oyster both call coastal estuaries their home.
But the two species may soon be facing a housing crisis prompted by climate change, as new research originating from UC Davis and published in Limnology and Oceanography suggests their habitat may soon shrink.
UC Davis environmental science and policy Professor Ted Grosholz led the study — funded by a California Sea Grant — with a team that included first author Jordan Hollarsmith, who is now a postdoctoral fellow at Vancouver’s Simon-Frasier University in Canada.
A four-year academic study funded by California Sea Grant and conducted by lead researcher Ted Grosholz of UC Davis found that oyster habitats in bays and estuaries along the California coast can be impacted by climate change.
The study, conducted from 2014-17, was performed in Tomales Bay and the research found that the greatest impact on oysters occurred in the earliest stages of development, particularly when the oyster was ready to start forming its shell.
Even moderate changes in water temperature, acidity and dissolved oxygen make it harder for native and commercial oysters to grow their calcium-based shells, a situation that does not bode well for the future, concluded a paper published this week in the journal Limnology and Oceanography.
It means the severe climatic changes predicted as the Earth warms over the next few decades could dramatically shrink the habitat for both farmed oysters and the native species that scientists have been trying desperately to restore, said Ted Grosholz, a professor of environmental science who led the study with funding from California Sea Grant.
The current reward for commercial fishers’ sustainability efforts? Of the 7.1 billion pounds of seafood Americans eat annually, over 90 percent is imported. Theresa Talley, researcher at Scripps Institution of Oceanography, published a report that found only eight percent of San Diego’s 86 seafood markets consistently carried local fish. This is bad news in many, many ways.
The California condor’s dramatic recovery from near-extinction was aided by removal of toxic substances from the land, which accumulated in animals whose carrion they ate.
But that recovery may be threatened in coastal condors by DDT-related contaminants in marine mammals, according to a preliminary study led by an SDSU researcher.
Coastal-dwelling condors have more of these compounds than those living inland, the study found. These are presumably absorbed from marine mammal carcasses, said study leader Maggie Stack. This might explain why coastal condors have thinner eggshells than those inland.
The preliminary findings were reported Wednesday by a team led by Stack, a California Sea Grant trainee and a graduate student at San Diego State University. Because the study has not been peer-reviewed, it requires further validation before it can be published, Stack said.
At the beginning of this century, the coho in the Russian River were almost completely eradicated.
“We were seeing less than 10 adults returning to the Russian River watershed, when years ago there were thousands of fish returning,” says Mariska Obedzinski, who helps run California Sea Grant’s Russian River Salmon and Steelhead Monitoring Program.
The Russian River watershed was once a stronghold for Central California’s coho salmon population, but Obedzinski says things like extreme habitat loss and drought years have led to the downturn.