With a welding hammer strapped to her wrist, Joy Hollenback slipped on blue fins and swam into the swirling, chilly Pacific surf one fall morning to do her part to save the lost forests in Northern California.
Hollenback floated to the rocking surface to control his breathing before free-diving into the dark depths toward the ocean floor. There, he saw his target: purple monkeys.
Within seconds, he crushed 20 to destruction. “When you’re angry, it’s a really inspiring way to get it all out,” Hollenback joked. “This is ecologically sanctioned chaos.”
The veterinarian, who lives in Berkeley, California, is part of a crew of volunteers who swim, snorkel, and dive armed with pickaxes and hammers on a mission: To crush purple urchins in bulk destroyed 96% of California’s iconic bull kelp forests between 2014 and 2020, and with it harmed the red abalone and other marine life they support.
The pilot project off the coast of Mendocino County is one of several initiatives that California is trying to save, such as leafy marine ecosystems, which are declining worldwide due to climate change.
Kelp forests play an important role in the health of the world’s oceans, one of the issues discussed at the United Nations climate summit in Dubai.
Based on early observations, efforts such as urchin culling seem to be helping.
Biologists say that they have begun to see small successes in experiments that were started a few years ago, which gives hope of reversing the destruction that is likened to a clear rainforest.
Healthy patches of kelp and schools of fish returned this summer in small sections where urchins were crushed in Caspar Cove, 160 miles (200 kilometers) north of San Francisco.
Near Albion Bay, where commercial divers took large numbers of urchins in 2021, biologists placed small lab-grown kelp on a 98-foot (30-meter) line. In August, they discovered that the kelp not only reached the surface but also multiplied.
“That’s the first time we know of that happening in an open coastal environment,” said Norah Eddy of The Nature Conservancy, one of several organizations participating in the experiment. “What we want is for the kelp to start putting babies in. It shows that these methods can be used in these types of harsh environments.”
There are still many major challenges to overcome before California bull kelp is on its way to recovery. But scientists say the progress has allayed fears that the forest will be lost forever.
“This is really setting up the system to hold the kelp we have until we’re in a better place,” said Kristen Elsmore, a senior scientist with the California Department of Fish and Wildlife.
Scientists will collect data over the next three years to determine which methods are most effective as California builds its first kelp restoration and management plan.
Kelp is so abundant that the state manages it as a single fishery, managing both commercial and recreational harvests. Under the plan, kelp will now be managed as an ecosystem, reflecting a greater understanding of the importance of kelp.
“Kelp forms a whole forest that supports a lot of other species, and so it has this effect on the nearshore ecosystem when you lose your kelp,” Elsmore said. “You’re losing an entire forest, not just a species.”
The plan could inform restoration efforts from Australia to Chile, where kelp faces similar threats.
“The ultimate goal is for these systems to actually be self-sustaining, and the restoration part is to give them a gentle push in the right direction,” said the scientist.
Kelp is disappearing as a warming planet raises ocean temperatures.
On the West Coast, the problem began after 2013 when a warm water system nicknamed “the blob” developed in Alaska and spread south, lingering for four years as it damaged marine ecosystems up the peninsula. in Baja California, Mexico.
At the same time, a mysterious wasting disease destroys the sunflower sea stars, causing their limbs to fall off and turn them into gooey masses, killing 90% of the population.
The starfish is the primary predator of the purple urchin. After the disease killed more than 5 billion sea stars, the urchin population exploded, gobbling up the kelp and leaving seascapes with almost nothing but spiny, globular echinoderms.
The loss of kelp prompted the California Fish and Game Commission to close its recreational red abalone fishery in 2018. Commercial harvests of red urchin were also hurt. Red urchins are favored over purple urchins because they have more edible uni or roe inside, but commercial divers say the amount decreases with less kelp.
Bull kelp, an annual seaweed, begins as a microscopic spore that grows up to two feet (.6 meters) per day until it reaches 98 feet (30 meters) before dying in the cooler months. It thrives in cool, well-drained water.
The coast of California has bull and giant kelp, the largest marine algae in the world. Urchins hurt both species, although giant kelp forests are better.
Some believe that the only way to restore the kelp is to reduce the purple urchins, which can lie dormant for years only to rise and eat the new kelp growth. Chefs started serving purple urchins to build a market.
“Sometimes it feels weird, like you’re killing this animal that’s a native species, but it’s for the greater good,” said Morgan Murphy-Cannella of the Reef Check Foundation, the kelp restoration coordinator. involved in kelp planting in Albion Bay. Its volunteers monitor kelp forests from Canada to Mexico.
Josh Russo, a former abalone fisherman and founder of the Watermen’s Alliance, a coalition of spearfishing clubs, helped start the urchin crackdown.
The first group was mostly local divers armed with sledgehammers, Russo said, laughing. After struggling to shake them under water, they resorted to small welding and furniture hammers and icepicks.
Volunteers removed 80% of the purple urchins from one section of Caspar’s Cove, Russo said. It is one of two places in California where licensed recreational fishermen are allowed to take an unlimited number of purple urchins.
But urchin crushing is not without controversy. Some fear it will spread urchin eggs, making the problem worse.
Russo saw no evidence of that. However, he said, the density of urchins has decreased in the 100-by-100-yard (91 by 91-meter) section, where schools of juvenile rockfish flowed this summer among the tall algae.
“It went from barrenness in the urchin to being full of life again,” Russo said.
Scientists say there is no substitute for natural predators, such as the sunflower sea star.
After learning to breed it in captivity, biologists established a stock to bring it back. Sunflower sea stars are present in four California aquariums, including the Birch Aquarium in San Diego, which induces spawning in three in October.
At least four sunflower starfish have also been spotted off the coast of Mendocino this year, which Elsmore said is “super exciting” because none have been seen in years there.
There is still much to learn. The kelp has not returned in all places where there are no more urchins, and scientists do not know why.
But crushing helps buy time to find permanent solutions.
The events run from April to September and draw people from all over Northern California.
On a Saturday in September, the volunteers included a paralegal, a factory worker, university students, and a landscape contractor, whose two Australian shepherds, “Swimmer” and “Breaker,” were patiently watching from the shore. An artist collects urchins to make purple dye for clothing.
Hollenback, the veterinarian, began participating in May 2022 after seeing events on Facebook. He hammered as many as 82 crows in 50 seconds before he could hold his breath. On this day, the sea in Caspar Cove was very rough, so the group diverted to the neighboring bay to look for urchins.
“It can feel counterintuitive to kill animals when my job is to save them,” he said. “But it helps save the whole ecosystem.”