Genetic study shows once-plentiful green abalone could thrive again along Southern California's coast

Jonathan Williams/Vantuna Research Group

Green abalone broadcast spawn to breed. NOAA and the Nature Conservancy recently funded a grant to see whether abalone bred in captivity can take hold where they've disappeared, along Palos Verdes.

Jonathan Williams/Vantuna Research Group

Green abalone are one of seven species of that type of sea snail along California's coast. Their historic territory stretched from central California to Baja Mexico.

Jonathan Williams/Vantuna Research Group

The green abalone population was decimated after they were fished hard in the 1970s. The fishery was closed in 1997. Some of the few that are left are a small handspan wide, near their maximum size.

Jonathan Williams/Vantuna Research Group

Green abalone are herbivores; they eat drift algae, and kelp, and breathe through pores near the edge of their very tough shells.


This story is part of our summer series "Beachcombing," in which KPCC reporters explore the ecology, economy and culture of Southern California's beaches and coast. Let us know what you think in the comments below or on KPCC's Facebook page.


A hundred years ago, one of the best cheap meals along the coast was abalone, a type of sea snail that lives on rock. But if you’re under 40, you’ve probably never even seen abalone, let alone tasted it. By the early 1980s, people had harvested so many of them that their population shriveled.

Now a new study, published in the journal Conservation Genetics, looks at the genetic makeup of green abalone. The study offers new hope about how the animal could rebound in local waters.

Geneticist Kristen Gruenthal, who works for the Hubbs-SeaWorld Research Institute in San Diego, says plenty of Southern Californians still have a romance with abalone “because people have this visceral tie to it. They grew up with these critters, and now they’re gone.”

California made taking green abalone illegal 16 years ago. But Gruenthal says so far the animals haven’t bounced back. At this rate it would be centuries before divers could again find them stacked four or five deep, as fishermen did in the 19th century.

Getting a genetic map of Southern California’s green abalone is the first step to helping the species reproduce faster.

Gruenthal and a team looked at tissue samples from abalone collected in dozens of places from Palos Verdes south to Swami’s Beach. “We found no significant differences in the genetics of abalone from San Diego county versus Catalina Island versus Orange county,” she says.

The genes may have been similar, but the way those genes expressed themselves in physical traits varied. Gruenthal says that’s good news for restoration efforts because you need a variety of physical traits to ensure a healthy population of abalone. 

Commercial fishermen are intrigued. Even a decimated abalone fishery -- 5 percent of its historic peak -- was worth millions a couple of decades ago.

Tom Ford is a scientist with the Santa Monica Bay Restoration Commission and a co-author of the study. He says abalone can also help strengthen marine ecosystems.

“They eat kelp, they compete for space and food with sea urchins and other herbivores,” he says. “And if we’re successful down the long run hopefully we’ll be able to get enough of these abalone going again to re-initiate a fishery in our area. But honestly that’s probably decades away.”

Ford says the new study’s a small step, but it’s already made another step possible. The National Oceanic and Atmospheric Administration and the Nature Conservancy have put up money to test captive breeding of abalone.  Ford says in a year, they could be transplanting juvenile abalone off the coast of Palos Verdes. 

An earlier version of this story incorrectly reported the organization for which Kristen Gruenthal works. 

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