That has changed in the past few years, as scientists learn more about urchin and kelp. The California coast has lost 96% of its seaweed canopy, due to imbalances in the marine ecosystem. The loss of the sunflower sea star, the only remaining predator for purple urchin, has allowed the urchin to graze on kelp unchecked. The urchin can survive in a dormant state for a long time, which means they don’t simply die of starvation when they’ve grazed a patch to the ground. The kelp plays a vital role in providing hiding places for other marine life, and slowing down erosion by diffusing the energy of oncoming waves.
Bennett Bugbee is a graduate student at Moss Landing Marine Labs, specializing in kelp. The phycology, or large algae lab, has been working on kelp restoration off the Mendocino coast since 2021. Scientists have figured out a way to encourage bull kelp to generate reproductive patches of spores called sori, in the lab. They have experimented by planting bags full of sori, or sori bags, in restoration areas. Last year, researchers from Moss Landing and Sonoma State University planted sori bags and placed rocks that had been seeded with lab-grown kelp into an area that had a low density of urchin. The remaining urchin devoured the kelp off the rocks, but an incidental circumstance led to a promising development.
“We had these lines out underwater to help us navigate between our plots,” he said. “And the kelp grew on those lines. Because bull kelp is buoyant, it started to lift the lines off the bottom of the ocean. And the urchins can’t get to it.” Last year at Albion, “We were able to grow bull kelp from spore to a full reproductive adult, in the ocean for the first time on the California coast in a restoration setting, so that's really exciting.”
This year, researchers will start a pilot study, planting the sori bags on elevated lines off of Portuguese Beach, which is part of the Mendocino Headlands State Parks. The goal is to restore five acres in the next two years. Rachael Karm is a research technician at Brent Hughes lab at Sonoma State University, working on the Portuguese Beach pilot restoration project. Kelp restoration consists mainly of keeping it away from urchin, which do great on rocks but don’t much care for sand. That works to the scientists’ benefit, according to Karm. They’ll plant the kelp in a patch that is surrounded by sand channels, “trying to really protect this patch and remove the urchin and then also have these traps around.” The urchin will already be deterred by the sand, but if they do make their way into the restoration site, they’ll be trapped. Researchers tested some modules about a month ago and then again over the holiday weekend. “They look really good, which is super promising,” Karm reported. “The kelp grew immensely in just one month.” She said the urchin removal at Portuguese Beach will begin soon, followed by outplanting the kelp on the lines.
The effort is funded by a two-year $1.6 million grant from the Ocean Protection Council and Sea Grant, which are trying to restore kelp across the state. Tristin Anoush McHugh is the kelp project director with The Nature Conservancy, which has long been at the forefront of kelp recovery efforts. She’s learned a lot about the most promising natural conditions for that 4% of the kelp that’s survived. For example, kelp cannot eat while holding onto rocks, so they tend to stay off of pinnacles, which are hit hard by waves. The kelp is also more likely to survive in freshwater confluences.
There have also been a few sightings of the sunflower sea star, including one off the Mendocino headlands about a month ago. However, there are still signs of the mysterious wasting disease that has destroyed the local population, “so we’re keeping a very fine eye on the recovery of any star, including sunflower stars,” McHugh cautioned. The sightings have included various sized sea stars, which is promising, and there are populations in Washington and British Columbia.
To learn more about the kelpfest events in Fort Bragg and Mendocino, many of them free, you can visit northcoastkelpfest.org
