CASPAR, CA, 5/3/23 — Cars lined the roadway on a misty morning in Caspar last weekend, as divers unloaded gear and Mendo Fire arrived with a compressor for refueling tanks. Only one person on the beach was a paid kelp restoration specialist; some 30 other volunteers of a range of ages had come on their own time and their own dime to get in the water and smash purple urchin.
“This is the first time [since the start of COVID-19] that I feel comfortable encouraging people in large groups to come up,” Joshua Russo, founder of our local Watermen’s Alliance for urchin removal efforts by recreational divers, told The Mendocino Voice. He was impressed by the turnout — in addition to locals, people had come from as far south as Santa Cruz and as far north as Humboldt to dive for overpopulated urchin that threaten the underwater ecosystem’s vital bull kelp forests. “This is hopefully going to be a really good year.”
Russo will rent a campsite in Caspar on the last weekend of the month from April through September this year, a practice he’s kept up since around 2017 to mobilize recreational divers after bull kelp saw declines of more than 90%. Recreational divers can smash purple urchin at a designated zone in Caspar Cove (and another in Monterey) under an emergency regulation that will sunset in 2024.
Divers can get in the water here any time — not only these group weekends — but Mendocino County’s remoteness makes things tricky, as normally compressors are not available to the public. Hence camping, tri-tip steaks, and collaborations with the fire departments and the Sonoma County Sheriff’s Office Dive Team to be able to reload tanks.
“You’re basically breaking eggs underwater,” said Russo of the urchin-smashing experience. He brings a furniture hammer and others dive with welding tools — the key is “small, pointy and light.”
“You don’t need a sledge hammer,” he laughed. “But the other thing is, if you use a hammer with a big head, when you swing it in the water, the water pushes it to the side.”
Smashing urchin is seemingly among the least elegant methods to restore the Mendocino Coast’s heavily depleted bull kelp populations. Other efforts locally and further afield include “green gravel” to reseed kelp; a crab pot-style trap to attract urchin and lift them out of the water; and attempts to resuscitate a struggling urchin predator, the sunflower sea star.
But this strategy is unique because it allows residents of coastal communities to get in the water and prevent their seafloor from turning to urchin barren.
“The results coming from this project are going to be very helpful in understanding how the recreational community can potentially participate in restoration efforts, especially at places that they’ve identified as being very culturally significant,” Tristin McHugh, kelp project director with The Nature Conservancy (TNC), told The Voice.
Recreational divers started out using culling methods similar to the hand-harvest conducted by commercial divers under a grant from the Ocean Protection Council (OPC), which culminated in a large report this summer. But commercial urchin divers are far more specialized and speedy at removing urchin — it’s easier for the average diver to use a hammer.
The work contributes to kelp research because participants fill out short surveys online documenting their dive after they get out of the water. As of Monday, McHugh said an estimated 70,058 total urchin have been culled over the duration of the project, with 104 dives total and 143 hours spent underwater.
“We’re allowed to do this as part of a [regulation change and valid fishing licenses], and part of that is documenting how much diver effort it took to get this success,” Russo explained. “It’s a very easy and basic reporting system where you estimate how many killed and tell them whether you’re scuba or free diving, that kind of thing. … The voluntary reporting is very important.”
Because sea urchins reproduce using broadcast spawning, in which their eggs and sperm meet in the water, there have been some concerns raised that smashing could have the opposite impact intended and increase urchin populations in a given area. That’s a reason to confine these efforts to small zones, where they can be studied as a possible solution without too much fallout. But Russo maintains that no evidence supports smashing increasing spawning — and for starving purple urchin from the North Coast’s urchin barrens, this is seemingly less of a problem.
Though the data collection is not at all conclusive yet, McHugh was willing to say that early returns on efforts in Caspar Cove seem promising.
“Anecdotally this year, folks have been successful in reducing urchin densities in the target area,” she told The Voice. “I feel confident in saying that.”
Russo added that divers have seen “baby kelp” growing at the site, even though these plants may not be visible yet from the water’s surface.
For McHugh, projects like this are crucial because they promote community investment — important in and of itself, but also something she hopes can foster more resources for restoration work.
“We’re still struggling to acquire multi-year funding for restoration work at large,” she said. “We do know that kelp forests research is very significantly less funded than other ecosystems. So, a lot of what we’re doing is trying to get kelp on the same playing field [as coral, or mangroves] to receive adequate funds to manage and understand the ecosystem.”
If you’re a diver and would like to get involved, more events are planned through September with the next on May 27. More information is available via the Watermen’s Alliance.
Note: Kate Fishman covers the environment & natural resources for The Mendocino Voice in partnership with a Report For America. Her position is funded by the Community Foundation of Mendocino, Report for America, & our readers. You can support Fishman’s work with a tax-deductible donation here or by emailing [email protected]. Contact her at KFishman@mendovoice.com or at (707) 234-7735. The Voice maintains editorial control and independence.