Artificial Reef Construction Underway

Sea fan on artificial reef

Small recruits of the sea fans Muricea californica (yellow polyps) and Muricea fructicosa (white polyps) on quarry rock boulders of the experimental reef. Photo by Greg Welch

June 30, 2008

Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334

Findings from a California Sea Grant study led by Todd Anderson of San Diego State University have been incorporated into the final design of a landmark artificial reef off Orange County.

In June, a skip loader began dropping watermelon-sized pieces of volcanic rock off Orange County to construct the reef, which will provide substrate for a150-acre kelp forest and will support the production of about 28 tons of kelp bed fishes.

Fish at the experimental reef

Kelp bass and other reef associated fishes at the experimental reef. Photo by Richard Herrmann

The $40-million artificial reef is being built by Southern California Edison as mitigation for damage from its nuclear power plant in San Onofre. Scientists say that it will be one of the largest and most advanced in the world.

Anderson, the director of the Coastal and Marine Institute at SDSU, studied fish production on three differently designed artificial reef modules for two years as part of a five-year pilot study led by the University of California at Santa Barbara for the California Coastal Commission. His research showed that all three “treatments” supported about the same level of fish production and this production level was about the same as that of a natural reef.

Anderson, however, was not able to answer the question he finds the most interesting: Is rocky reef habitat in short supply in the region?

LiDAR at work

Giant kelp grows on a rubble concrete module of the experimental San Clemente artificial reef. Photo by Richard Herrmann

“Artificial reefs attract fish and they produce fish, but what I really want to know is whether they actually add to the total fish production in the region,” he says. In other words, would the fish have settled on a natural reef nearby? “We still don’t know whether hard-bottomed habitat is a limiting factor for fish production in the region.”

Anderson is currently studying the links between the sizes of predatory fish on fish recruitment success at Catalina Island. He also has a project with a NOAA Fisheries biologist on coral reef recruitment as a function of habitat type off Midway Island.