Terry Sawyer is on a mission to rescue oysters from newly hostile seas. Sawyer has been farming these briny bivalves for almost 30 years in Tomales Bay, north of San Francisco, at Hog Island Oyster Company. The business he co-owns sells $9 million worth of Sweetwaters, Kumamotos, and Atlantic oysters a year at the company's two local oyster bars, at nearby farmers markets, and direct from the farm to hungry consumers who can't seem to get enough of this sustainable shellfish. But Sawyer's seafood business is threatened by ocean acidification (aka climate change's evil twin) and he and other oyster growers are working overtime to find creative ways to save these sea creatures -- and their own livelihoods.
As the ocean absorbs carbon dioxide from the air like a sponge, it also grows increasingly acidic. As a result, baby bivalves, or “oyster seeds,” have a tougher time growing shells and maturing into those plump, juicy adults destined for dinner plates. (Acidification, which lowers the pH of salt water, has also recently been shown to make for a hostile environment for other marine life, such as sea snails.) This shift in the chemical makeup of seawater started wreaking havoc in Washington a few years ago, when Taylor Shellfish Farms and Whiskey Creek Shellfish Hatchery began losing large numbers of oyster larvae.
But the Pacific Northwest wasn’t alone in this predicament: California’s oyster industry has long relied on hatcheries in Oregon and Washington for its oyster seeds. "We're getting squeezed," Sawyer told a group at a recent tour of his farm. "While demand is growing, seed sources are dying off. We're talking about a paradigm shift."
In previous years, Sawyer said he bought some 7 million oyster seeds from hatcheries. (There's a significant mortality rate from seed to market; on average only 50 percent survive in the 18 months to three years it takes for an oyster to mature.) This year, he could buy just 2.5 million seeds -- supplies are down as a result of this problem -- and they were much smaller than the typical six-millimeter size he used to purchase, which significantly lowers the oysters' chances of survival.
So, out of necessity, Sawyer finds himself in the oyster seed growing business. And he's solicited help to keep his baby bivalves alive. Hog Island has partnered with scientists at UC Davis's Bodega Marine Laboratory to keep close tabs on these vulnerable young oysters in the same waters where they used to thrive without much fuss. Such collaboration between scientists and shellfish industry innovators to study, and, ideally, minimize the damage caused by ocean acidification has already taken place at Whiskey Creek with scientists from Oregon State University and will likely be replicated all along the western coastline, said Tessa Hill, lead scientist on the Hog Island partnership.