In one nine-hour day this week, longtime fishermen Terry Herzik and Gary Thompson smashed more than 10,000 purple sea urchins on the floor of a cove off the Palos Verdes Peninsula.
But that’s just a drop in the bucket… The pair have millions more of the spiny invertebrates left to hammer, even though they — along with other partners — already have gotten rid of about 1.6 million in just two coves off the Peninsula.
As tedious as it sounds, the work is necessary as part of a kelp-restoration project that began in July 2013.
“We’re killing the sea urchins that have overrun this kelp habitat so much that there’s not a speck of growth on the bottom where we’re working now,” Herzik said. “It’s like the inside of a bathtub almost. They’ve just eaten every last microbe.
“Most of the urchin fishermen think it’s hopeless, but I think this is going to be the wave of the future.”
Herzik and Thompson have been diving for urchin and sea cucumber together on the Sun Star for a decade, but they can’t harvest the purple ones that litter the bay because they are too diseased and malnourished. Even though the urchin’s gonads are eaten as a popular food item called uni, these hardy animals off the Palos Verdes Peninsula can’t grow large enough to be harvested because they have very little food to eat. Instead of dying of starvation, they persist in a listless vegetative state for years.
“They eat everything. I saw them years ago munching on a canvas tennis shoe,” Thompson said. “You feel bad (killing them) until you realize there’s billions of them and they’re just like weeds.”
Once the urchin are gone, scientists believe the giant kelp forests will return along with more than 700 species that were native to the area before the industrialization of World War II led to the urban runoff, pollution and overfishing that created the current environment.
Last year, the The Bay Foundation, formerly known as the Santa Monica Bay Restoration Foundation, began the project by focusing on removing entire areas of all but a handful of urchin at a time. That way, the animals don’t have enough time to overwhelm an area before the kelp can grow. Forty divers working full- and part-time for the past 12 months have cleared 13 acres of the Honeymoon and Golden coves off the Peninsula. About 140 more acres are left to go.
The work, funded by a foundation set up by the polluters responsible for dumping as much as 1,000 tons of DDT and polychlorinated biphenyl into the Palos Verdes Shelf from the 1950s to the ’70s, is a joint venture with volunteer divers from Los Angeles Waterkeeper and a few urchin fishermen, as well as other research institutions monitoring the success. Herzik and Thompson joined The Bay Foundation’s effort because they believe it will help restore a once-thriving fishery and also because the work is rewarding.
If the work is deemed a success, it will provide direction to scientists and environmentalists around the world.
“Urchin barrens like those off of Palos Verdes are part of a global phenomenon,” said Tom Ford, executive director of The Bay Foundation. “It’s not just a local thing. Last week we had Japanese divers here” learning about the project in hopes they can do the same on their coast.
This project is distinguished from previous kelp-restoration efforts because it focuses on clearing one area at a time rather than haphazardly removing urchin. The animals are quick to resettle an area that’s been cleared. But, by leaving only two urchins per square meter, the team has been able to keep them at bay while kelp and other life returns.
“This is the first time we’ve really been able to do this full sweep of scientific investigation,” Ford said. “Once the urchin are cleared, if you come back the next day, you start to see a film of algae growing on the rocks. We’ve had individual kelp plants that made it to the surface in great ocean conditions in only 10 weeks. They like cool, clear water and lots of sunshine.”
So far, the results are inspiring. The halibut, kelp bass, garibaldi, California sheephead, California spiny lobsters, two-spot octopus and other species native to the local ecosystem return within months to areas where kelp plants have sprouted. Scientists ultimately hope to see urchin competitors like abalone and predators such as sea otters return.
Research sponsored by The Bay Foundation, Santa Monica Baykeeper (now L.A. Waterkeeper) and Occidental College found that the quality of purple sea urchin is likely to improve considerably once kelp forests return. The sickly, starving animals that exist now will be replaced by larger, healthier ones that can be fished, according to a report published last year in the journal Ecosphere, titled “Kelp forest habitat restoration has the potential to increase sea urchin gonad biomass.” It found that, with the return of kelp forests, the gonads of purple sea urchin would likely increase by nine times that of their existing average size now in the bay.
A healthy ecosystem also will help fishermen make up for the loss of fishing in state-imposed Marine Protected Areas off Point Vicente and Abalone Cove, where urchin harvesting and other fishing have been banned since 2012, local environmentalists believe.
The California urchin fishery generated $7.4 million in 2010 and was ranked fourth by weight that year, with over 5,000 metric tons brought in to land.
On Tuesday, Herzik and Thompson cleared about 200 square meters of urchin in about nine hours of diving with hammers off the Palos Verdes Peninsula. It’s long, tedious work holding fast to rocks while they smash away. But the men agree it’s worth it.
“It’s totally amazing,” Herzik said. “The growth starts with a little film of algae on the rocks, and then little sprouts start showing up — and that’s the giant kelp. It grows incredibly fast once it takes hold.
“Then, in two or three months, here come the halibut, kelp bass, barracuda, sculpin and sheephead.”
Photo caption: Local fisherman Terry Herzik has been helping The Bay Foundation remove purple sea urchin along the Palos Verdes coast because they eat kelp and ruin fish habitats.
View original article at: Divers hammer thousands of urchins to save Palos Verdes Peninsula kelp forests