He's Helping Super Oysters Survive Climate Change

He's Helping Super Oysters Survive Climate Change

By Tafline Laylin

Joth Davis, who has spent his entire adult life breeding, researching and selling shellfish, is concerned about making the aquaculture industry more sustainable.
SourceTafline Laylin/OZY


Because the global food supply is more tenuous than you think.

By Tafline Laylin

Joth Davis points to a sea lion splashing in Clam Bay. He has emerged from a dock wearing waders on a brisk fall day at a National Oceanic and Atmospheric Administration research center in Manchester, Washington. We’re meeting for what turns into a crash course in shellfish sex 101.

The sprawling facility hosts a number of activities, including the Pacific Hybreed laboratory, a tiny hatchery that Davis, 64, founded with his partners nearly two years ago. Their goal? To develop super shellfish that can withstand disease and climate changes threatening an industry worth some $340 million just in the U.S. — not to mention an important food source. Yes, your fried scallops and oysters on the half shell are in danger.

Davis, who has spent his entire adult life breeding, researching and selling shellfish, is concerned about making the aquaculture industry more sustainable. Considering the environmental impact of growing “high-quality protein” such as pigs and cows on land, he says, humans are going to have to get more adept about using the sea.

But perils exist there too. The rise in global temperatures has altered the chemical makeup of our oceans in such a way that shellfish struggle to grow their shells — and survive. In addition to ocean acidification (OA), Ostreid herpesvirus 1, or Pacific oyster mortality syndrome (POMS), can decimate up to 95 percent of an oyster crop, according to Davis. In 2010, New Zealand lost half of its farms to the incurable disease. Cue Pacific Hybreed.

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Researcher Jeremy Esposito shows just a few of the thousands of tiny baby oysters he is helping to raise in the Pacific Hybreed laboratory in Manchester, Washington.

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Joth Davis demonstrates how to get a scallop to open by essentially irritating the shellfish.

Davis and his partner, Dennis Hedgecock at the University of Southern California, are using crossbreeding to develop high-yielding shellfish (starting with popular Pacific oysters and then moving on to rock scallops and other species) that are less susceptible to OA and POMS. This involves breeding a male and female and then breeding sibling offspring — an inbred line.

“Now that sounds bad,” says Davis, “but it’s actually integral to the process.” They do this, say, 100 times within one family and another 100 times with a separate family. Then they create pair matings of two separate inbred lines, called a hybrid. Two unrelated hybrids are then bred to create a double hybrid. Davis says they can uncover genes that will result in potentially high-yielding, disease-resistant specimens that can thrive in a variety of locations using less space than usual. If all goes to plan, they will sell these super-resilient shellfish seeds to commercial outfits for a share of any resulting profits.


But for Stan Allen, this technique is worrisome. Most scientists working on behalf of industry use the time-honored method of selective breeding to make genetic gains, says the professor at the Virginia Institute of Marine Science. Crossbreeding, Allen cautions, is more experimental and has never been applied commercially in shellfish. This “makes it exciting and scary at the same time.”

Davis, who jokes about sparring professionally with his East Coast colleague, counters that selective breeding narrows the gene pool. That’s not good for oysters, he says. “So the whole nature of selection is that you have to continuously figure out ways of bringing in new genetic material while maintaining the traits that you like, and it’s tricky long-term to do that.” Skirting those issues, Hedgecock and his USC colleague Donal Manahan are developing genetic markers that make it possible to identify the good genes within days, allowing them to bypass months or years of testing. Davis calls his partners the company brain trust, but he’s not exactly hollow in the head either.

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According to Davis, purple-hinge rock scallops like these are one of the most ideal aquaculture candidates given that they grow to be quite large in a relatively short period of time.

Allen, who has known Davis for decades, describes him as “cosmopolitan” — an unusual descriptor for a scientist. But it fits. In 1989, while working on his Ph.D. at the University of Washington, Davis and his first wife (who died in 2010) started Baywater, Inc., a commercial shellfish farm. Now one of his two sons, Caleb, runs the business while he spends time on other pursuits such as growing kelp and working as a senior scientist with the Puget Sound Restoration Fund. Davis also has a daughter and remarried to a family friend six years ago.

Retired retailer Wyatt Garfield details his close friend’s passion for work, noting with awe Davis’ ability to mentor students, apply for grants and publish — on top of his other pursuits. Davis also put 20 years of research, development and exploratory trips to Japan into Taylor Shellfish Farms, Inc., one of the largest shellfish companies in the U.S. There he met Hedgecock, before the two broke off on their own. Now he is devoted to getting Pacific Hybreed off the ground and spreading sustainable shellfish seed all over the world.

Their research is privately funded, though the monthlong partial government shutdown has impeded their work because they can’t access the federal research lab except to care for animals. Davis says they are close to securing funds to ship a container lab to Hawaii. The warmth and sunshine there fuel algae growth, which is food for shellfish, so they can raise a generation of super oysters in 10 to 12 months, versus two years in Washington. If all goes to plan, he hopes to commercialize genetic lines of super oysters within two years.

In the meantime, I ask how he deals with the dearth of political will to address climate change, which has caused so much destruction in his industry. “I live in a world of hope,” he says. “Farmers are optimists. They have to be.”

Read more: Julia Roberson is out to save our oysters, but she’s no marine biologist.