Beachgoers are familiar with the tangled masses of tan seaweed that wash up on shore, but many have never seen the majestic forests of giant kelp thriving underwater, providing shelter and food for hundreds of species of fish, invertebrates and algae.
“Kelp forests are an amazingly unique ecosystem in California,” said Chuck Kopczak, curator of ecology at the California Science Center. “The only place where we find this species of kelp growing into forests is on the Pacific coast of California north of the equator. It’s a very special ecosystem, and one of the most diverse ecosystems, second only to coral reefs and very close to rainforests on land.”
Within the last 100 years, though, development, runoff and pollution have caused a significant loss of the area’s once-abundant kelp forests.
“Over the past 15 years, my colleagues and I have been looking at the trends of the amount of kelp off the coast and investigating its decline,” said Tom Ford, director of marine programs at the Santa Monica Bay Restoration Foundation. “Based on 100 years of historical data, there has been a 75-percent decline starting in the 1940s.”
The rocky bottom of the ocean, where kelp once anchored and grew, has been overtaken by purple sea urchins eating anything they can find and creating acres of barren rock.
“When outbreaks of sea urchins occur, usually predators take care of it,” Kopczak said. “Unfortunately, we eliminated a lot of predators: lobsters, otters, sheepshead fish. The only mechanism to naturally remove urchins is storms, which would reduce their numbers. But we don’t get storms. We’re forced, if we want the kelp forest, to reduce the population of sea urchins.”
To do so, trained divers participating in the Palos Verdes Kelp Restoration Project have been reducing the number of purple sea urchins to two per square meter. Supervised by professional marine biologists, the divers use geology hammers to cull the urchins.
The Kelp Restoration Project, led by the Santa Monica Bay Restoration Foundation, is supported by a number of partnering organizations: California Science Center, Los Angeles Waterkeeper, California Sea Urchin Harvesters, Vantuna Research Group, National Oceanic and Atmospheric Administration, Department of Fish and Wildlife, and Southern California Marine Institute.
Funding for the project comes from the Montrose Settlements Restoration Program, consisting of six federal and state agencies with NOAA as the lead agency. According to SMBRF, MSRP has allocated funds to restore natural resources harmed by polluters that released pesticides and toxic pollutants into the Southern California marine environment.
The project started the first week of July, and now, 10 weeks into the four-year effort, the marine biologists monitoring the areas are seeing kelp budding and growing — promising evidence that a kelp forest could reestablish itself and bring many kinds marine life back to the waters off the Palos Verdes coast.
“Restoring kelp has possibilities of increasing local fish stocks in a tremendous way, for example, kelp bass, sand bass, yellowtail ... these are among the species that are associated with kelp,” Kopczak said.
Past efforts to reduce the sea urchin populations have proved successful in allowing kelp to grow.
“Our efforts started 15 years ago in Malibu and off Long Point, along the area that later became Terranea,” Ford said. “In both Malibu and PV, we were able to demonstrate that if we reduce the density of sea urchins to two per square meter, the kelp forests would naturally regenerate in these areas.”
Their efforts paid off quickly, Ford said, with the kelp forest growing from microscopic to 30 feet tall in eight months in Malibu, and the same results off Long Point within 15 months.
When Ford spoke to the News in late August, he said those monitoring the current site saw juvenile giant kelp that was 1 inch to 2 inches tall.
“Now it’s probably 4 inches tall,” he said.
The current climate is good for giant kelp, Ford said. “The cold water is filled with nutrients, and the reproductive output of the kelp where it is growing is plenty to reseed these areas,” he said. “All we have to do is get rid of the excess urchins so the kelp can naturally reestablish itself.”
That’s one of the beauties of this project, Kopczak said.
“We’re not talking about an invasive species, it’s a naturally occurring species, just that the system is tilted out of balance by human activity,” he explained. “It’s incumbent upon us to step in and do something. Reducing the urchins to normal levels will give kelp a chance to get a foothold, and that will give the system a chance to go back to a balanced state.”
When the current project is done, Ford said, “we expect to see a 300-percent increase in the amount of fish, and a 900-percent increase of harvestable red sea urchins for industry.”
There is still a great deal of monitoring to do as divers clear acres of sea urchins, and SMBRF is looking for more volunteers.
“We’re spinning up this project,” Ford said. “By next summer we’ll have 13 boats out there working to make this happen. It requires a significant effort.”
For more information, visit www.santamonicabay.org.