Zombie Sea Urchins Are Wreaking Havoc on Local Ecosystems, But There's Hope
Photo by Mark C Anderson
By Mark C Anderson, January 6, 2024
An unprecedented underwater crisis has been unfolding along the California coast, including in Monterey Bay.
The crisis is a massive population of purple sea urchins blanketing huge swaths of near-shore ocean floor. It’s a problem because they eat giant kelp from the roots up, destroying the underwater forests that are essential habitat for fish, invertebrates and marine mammals.
Fortunately it’s been met by an innovative and unprecedented solution: an uncanny collaboration between commercial urchin divers, aquaculture farmers, environmentalists, marine scientists and restaurants.
An exploration of their collaborative response to the slow-creeping urchin attack debuted in the fall issue of Edible Monterey Bay, and appears below, with permission.
A quick update, in three parts:
The Moss Landing Marine Lab (MLML) work to optimize diet and aquaculture conditions for purple urchins is ongoing,
A number of petitions—some to cull sea urchins, others to allow divers to harvest them in marine protected areas—will be considered by the California Department of Fish and Wildlife in coming weeks and months.
While sea urchin ranchers haven’t been able to acquire as many sea urchins to fatten up as they would like (see the story below for more), demand for sea urchin remains high among restaurants and seafood merchants. “The distributors want them!” MLML aquaculture expert Luke Gardner says. “We don’t want to keep telling them we don’t have them.”
Sea Urchin Ranching: Efforts to save the kelp forest with urchin harvesting prove appetizing.
A zombie apocalypse is wreaking havoc on local habitats. And one surprising way to fight back is dining out—and eating uni—at some of the best restaurants in the area.
The annihilation has gone unnoticed by many because it’s happening underwater.
All along the California coast, purple sea urchins have gobbled up whole forests of giant kelp.
After they’ve consumed all there is to eat, the urchins survive despite braving starvation, in a hibernation-type state, creeping around the ocean floor like the undead, forming spooky and spiky fields of purple called “barrens.”
Commercial scuba diver Grant Downie, who’s been harvesting urchins professionally for more than a decade, is familiar with the hollow reality.
“There’s no uni inside, no nutritional value,” he says. “It’s just a living, empty shell.”
Villainous disasters with cinematic names—The Blob and sea star wasting disease—helped create the urchin-kelp crisis, and hit local ecosystems starting around 2013.
The Blob is how scientists described a years-long marine heat wave that diminished oceanic nutrients kelp depends on, while also suffocating the towering plants with its warmth. Around the same time, the mysterious wasting disease started turning sea stars, which are prime sea urchin predators, into mush.
While some may have observed less kelp at the surface of places like Lovers Point cove, down below the effect was impossible to miss—the rough equivalent of visiting a redwood grove that’s standing there one month, then gone the next.
“When I first started diving, the kelp was so thick you could hardly swim through it,” says Downie, a second-generation dive pro. “We lost about 90% of the kelp along the Northern California coast and it hasn’t rebounded.”
A group of volunteer recreational divers launched the Giant Giant Kelp Restoration Project in 2018 and systematically smashed urchins with hammers. Thanks to their efforts culling hundreds of thousands of the sea hedgehogs, an entire 11- acre area of giant kelp off Monterey’s Del Monte Beach recovered.
But the California Department of Fish and Wildlife didn’t renew its permit to cull urchins, in part because officials weren’t in love with the idea of killing a native and noninvasive species.
Fortunately, a group of ocean experts was at work on another type of zombie warrior strategy starring aquaculture and capitalism.
DOUBLE DIVIDENDS
Down under Monterey’s commercial wharf, a former zombie has a new lease on life. And a destiny in fine dining.
This particular sea urchin was caught off the shores of Fort Bragg by commercial divers—where a number of them ply the trade, compared to the Monterey Bay, where very few do—then delivered to Monterey Abalone Co.
MAC’s team then fattened up the little echinoderm orb and hundreds of others on a diet of kelp they’re accustomed to feeding their shellfish. Then they sold the urchins at a premium—uni, after all, is a delicacy that can sell for upwards of $275 a pound.
MAC operations director Kaitlin Rooney sounds more than pleased with the chance to ranch urchins.
“The project has been very successful, in terms of aiding in kelp restoration efforts and providing a great product to a large consumer demand,” she says.
This solution to the apocalypse started as part of a hands-on aquaculture class project at Moss Landing Marine Laboratories, part of San Jose State University’s College of Science.
Helping lead the way was Ph.D. marine science specialist and research faculty member Luke Gardner, whose work is funded by California Sea Grant, a National Oceanic and Atmospheric Association program that partners with universities to, per its mission, “create and maintain a healthy coastal environment and economy.”
“We wanted to find out if we can economically incentivize the removal of sea urchins,” says Gardner. “Time and time again humans have shown a proclivity to take something from the ocean if there’s money in it. In this instance, it’s constructive and not destructive.”
When the MLML graduate students successfully harvested and plumped up hundreds of urchins—“They went from cobwebs inside to ready for market!” he says—they got more ambitious.
The group authored a successful grant proposal and promptly enlisted partners to test out three different ways to rehab hungry urchins: 1) in a converted shipping container using recirculating sea water; 2) at a flow-through farm near Santa Barbara with water pumped from the Pacific; and 3) in cages attached to a Monterey Abalone Co. barge floating in the harbor near Fisherman’s Wharf.
Meanwhile, Middlebury Institute’s Charles Cogan, director of research for the Center for the Blue Economy, helped track everything from man hours to facility costs.
“We looked into the economic feasibility of the whole process,” Cogan says, “and how to scale it so we can really bring this to people in California, and anyone else that wants to do an urchin ranching startup.”
As this goes to print, Gardner is readying a report for the project’s primary underwriter, the nonprofit Pacific States Marine Fisheries Commission. The analysis notes the floating barge system proves most profitable, and that other benefits besides zombie mitigation materialize, including cooperation between groups that have historically been at odds.
“U.S. aquaculture production lags far behind many other countries partly due to negative social perceptions,” the report reads. “One strategy to overcome such impediments to marine aquaculture is to align economic and environmental interests of traditionally opposing groups: fishing, aquaculture and environmental nonprofits. The purple sea urchin barrens causing mass deforestation of kelp in California and Oregon provide an opportunity to do such.”
The ranched urchins can go from famished to flourishing in as little as six weeks. As Gardner points out, “That’s a good turnaround for a luxury item.”
TASTE TEST
Chefs like Aubergine’s Justin Cogley serve the ranched uni—first and foremost—for the flavor and texture. But he knows his audience basks in a backstory that what tastes so good is doing good too.
“Diners come with greater and greater expectations to have something new and exciting— amazing product isn’t enough, there has to be the wow factor,” he says. “Guests who seek out restaurants like ours look for stories like this.”
That story sweetens with an additional layer: Sea Grant and Moss Landing Marine Labs have visited farmers markets to pick up leftover produce to feed the urchins, and conducted talks with Taylor Farms to do the same with scraps left behind after harvest.
“It’s an extra loop on sustainability since we can make the most of something the farm wouldn’t have used,” Gardner says. “Urchins aren’t picky eaters, and it’s fascinating to taste how the feed influences flavor.”
Spinach-fed urchins turn out to be particularly yummy, he continues, before adding another uplifting element: While two of the three ranching trials proved profitable—with the pump-through model difficult to implement because piping from the Pacific is both expensive and nearly impossible to permit— the trials represent rudimentary attempts by a raft of rookies.
“The first time you do anything you’re going to be inefficient, if not outright terrible,” he says. “As we really zero in on what matters, things will get a lot better.”
That last thought rings like a proverb worth reiterating—and celebrating, perhaps with a tasty plate of uni.