Beloved Pismo clams make a mystifying comeback

PISMO BEACH — Once a cherished local fishery, Pismo clams went missing from their namesake beach for decades.

The treasured shellfish, however, are now making a steady, triumphant return. No one knows exactly why. But Ben Ruttenberg, the director of the Center for Coastal Marine Sciences at Cal Poly in San Luis Obispo, is determined to find out.

In 2014, when the clam population was still languishing, Pismo Beach city officials asked Ruttenberg if he could find out how to bring the clams back to the city’s beaches.

“We said, ‘Well, that’s a great idea,’” Ruttenberg recalled.  “And then we realized that it was a lot more complicated than the simple question that they were asking.”

To truly understand the life cycles and movements of Pismo clams and unravel the mystery of why they’re making a surprise comeback, students from his lab are doing monthly clam surveys and also festooning the mollusks with identification numbers, QR codes and metal washers that allow clams buried in the sand to be found with metal detectors.

During the Pismo clams’ glory days in the 1950s, marine biologists had come up with estimates of the growth rates and lifespans of the clams. But Ruttenberg discovered that nobody knew if the estimates still held true for today’s Pismo clam population. He also learned that no one had studied how the clams move around throughout their lifetimes.

“We realized that there was this incredible vacuum of information about this cool creature that was so culturally important here,” Ruttenberg said.

The QR codes on the buried clams link to a survey, where clam-spotters can report information about the clams’ location and well-being. Since Ruttenberg’s team reburied more than 400 of the QR-coded clams in August and October, beachgoers have found 44 of them.

“It’s definitely like a science treasure hunt,” said Marissa Bills, a graduate student in marine biology who currently leads the Pismo Clam Project in Ruttenberg’s lab. “We know that it’s working, which is very exciting for us.”

California Department of Fish and Wildlife officers, meanwhile, are aiding in the clams’ revival by counting the thousands of clams they rescue from poachers each year. The officers then rebury the mollusks and share their data with Cal Poly researchers.

You couldn’t blame visitors to Pismo Beach, a surfing town with retro vibes and broad beaches, for thinking it’s still the “Clam Capital of the World,” a title the city claimed in 1947. Pismo Beach’s three giant concrete clams still greet motorists entering the downtown. And this fall, the town celebrated the 75th anniversary of its annual clam festival, replete with clam costumes, a parade and chowder made from non-local clams.

So it may be easy to forget that overfishing nearly drove Pismo clams away from the area. No one has recorded a clam big enough to legally harvest — 4.5 inches or larger in diameter — at Pismo Beach for almost three decades.

“They used to till up this beach and sell the clams for pig food,” said Lt. Matthew Gil, a game warden with the Department of Fish and Wildlife. “Hundreds of thousands of clams! They didn’t start regulating until it was way too late.”

Some harvestable Pismo clams can still be found in a smattering of places on the California coast, including the Monterey Bay area. But when Ruttenberg’s team began conducting clam surveys on Pismo Beach in 2014, he said, “we would spend four hours digging and find nothing.”

But two years later, the team began noticing something remarkable: More and more Pismo clams were turning up on their digs. The clam population continued on a promising trajectory over the next five years. And then last summer, Ruttenberg and Bills saw the clam population explode.

“There are more Pismo clams on the beach right now than there have been in any of the years that we’ve been monitoring them,” Bills said.

No one knows exactly how many clams now call Pismo Beach home, but judging by the number confiscated from poachers of late, it could be in the hundreds of thousands or even millions. Bills is currently crunching the numbers to develop an informed estimate.

Despite the return of the natives, Gil said, the clams remain under threat from humans.

Poaching has always been a serious problem in Pismo Beach, but the pandemic made it much worse when cooped-up Californians flocked to the town and found it studded with tasty-looking clams.

Gil said 2020 was the worst clam poaching year on record. Fish and Wildlife officers seized more than 25,000 clams along a 3-mile stretch of Pismo Beach. Last year was better, but poaching is still the biggest threat to the clams’ recovery, Gil said.

“I used to write a citation and think, ‘What difference did I make for that species?’” he said.

So now his department doesn’t just track the citations it issues.

In addition to counting and reburying seized clams, the agency has also begun collecting the ZIP codes of poachers. That will allow the state and the Cal Poly team to create and test outreach efforts to discourage poaching.

The department’s new signs in Pismo Beach share facts about the clams’ biology, list clamming regulations and demonstrate correct reburial techniques in both English and Spanish.

“The last two years, we’ve been going out on the beach and actually talking to families and kids,” said Claudia Makeyev, an environmental scientist who coordinates outreach and education in the department’s Pelagic Fisheries and Ecosystem Program.

“They have no idea that there’s even regulation, let alone a size limit, let alone that you have to rebury them,” said Makeyev, who noted that kids are usually happy to make a game of reburying the clams.

The biggest threat, Makeyev said, comes from those poachers who are less susceptible to outreach.

“Really serious poachers who are willfully ignoring the rules and regulations — those are the ones that are doing the most damage,” she said.

Fish and Wildlife has increased the number of dedicated patrols of Pismo Beach, keeping an eye out for premeditated and organized poaching. Initial fines can be as high as $100,000.

Gil said it’s been heartening to see Pismo Beach residents talking to fellow beachgoers about the clams and discussing how to protect them.

“I never thought I’d see a clam comeback in my lifetime,” said one excited older man who recently approached Gil on the beach. “We used to come here with buckets to collect clams.”

The Cal Poly team has been met with similar excitement. “Every time we’re out doing a survey, there are older community members that come over, and they are just fascinated by what we’re doing,” Bills said. “They all remember clamming when they were children.”