A kelp forest is coming back in force since volunteer divers cleared away more than a million urchins from the rocky bottom of the ocean off the Palos Verdes Peninsula over the past year, drawing hungry spiny lobster, bass and octopus, a nonprofit environmental group reported today.
The Bay Foundation, in partnership with environmental groups, fishermen and researchers, have been clearing the purple sea urchins since last year, according to Julie Du Brow, a spokeswoman for the foundation.
A survey of the four-year kelp restoration project’s first year shows a significant return of kelp, other algae and fish, she said.
The peninsula, recognized as one of the most important kelp forest regions on the West Coast, experienced a 76 percent decline in the kelp forests over the past 100 years, impacting the stability and sustainability of the iconic giant kelp ecosystem and its associated economies, according to the foundation.
The formerly healthy kelp forests, often referred to as the “tropical rainforests of the sea,” supported hundreds of species of fish, invertebrates and other algae and were popular fishing spots. When kelp forests are decimated by too many urchins, “urchin barrens” are established.
“Once established, urchin barrens can remain in place for decades as has been the case off of Palos Verdes,” said Tom Ford, the project leader and TBF’s executive director. “These barrens, true to their name, consist of rocks and urchins covering the sea floor, crowding out most other life.”
Included in the group of volunteers are members of California’s sea urchin harvesters, which sell the urchins to local restaurants to be served as “uni.”
According to the survey, there are now hundreds of giant kelp, some reaching lengths exceeding 25 feet, at or near the water’s surface. In addition, fish species richness has doubled in the restoration sites.
“The changes to the ecosystem from the restoration efforts have been very direct,” said Jonathan P. Williams, research scientist and adjunct instructor at the Vantuna Research Group-Occidental College.
“The kelp has returned and we’re seeing the occasional green abalone settle into the depressions on the reef,” he said. “Currently, there are a lot of herbivores grazing on the new turf algae. But as the restored reef is quickly maturing, more predators are showing up.”