There are 27 oil platforms located off the coast of California nearing the end of their useful life in oil and gas production. As multiple government agencies and stakeholders work to decide their fate, Biological Sciences Associate Professor Jeremy Claisse is part of a group providing critical data on the role of these structures as unexpectedly good habitat for marine life.
Claisse grew up fishing and diving along the Southern California coast. For the last 15 years he has focused his research on the ecology of marine life associated with reef ecosystems. More recently, he has been analyzing fish assemblages around those oil and gas platforms with comparisons to natural habitats.
"What we found is that some of these platforms are amazingly productive," said Claisse. Because the platforms rise all the way from the sea floor to the surface, fish in different life stages use different parts of the platform. The younger fish are using parts of the structure that are high in the water column away from the bottom. As they get older and bigger, for the most part, they move towards the bottom.
"For some platforms and for some species of fish, you get a really large number of really big individuals living around the base of these platforms. When you calculate how many eggs and larvae these fish would produce, you find that for some species on some platforms, it's tens to hundreds of times more than the average on natural reefs in the region."
The structures have also accumulated large masses of invertebrate marine life.
Prof. Claisse conducting rocky reef surveys as part of a project examining the impacts of marine protected areas in Southern California.
The future of the structures is complicated. Four platforms are in state waters (up to three miles from shore), and the remaining 23 are in federal waters. As part of the decommissioning process, decisions need to be made individually for each platform on whether to remove it completely, to remove the top portions of the structure and leave the rest to continue function as an artificial reef for fish and invertebrates or to repurpose the platforms for research or in other ways. Holly, a platform off Santa Barbara now managed by the state, is going through the decommissioning process now.
A recent three-day forum to discuss options for the future and related science held at the Aquarium of the Pacific included representatives from federal and state agencies responsible for the oil platform decommissioning process, operators who run the platforms, fishing industry representatives and academic scientists. Claisse was among the scientists providing critical information on the habitat value of these submerged steel structures. The aquarium released a report summarizing the proceedings and findings on March 4.
"The big take away for me was how amazingly complex the legal and technical issues of actually getting the permits in place to remove the platforms or make some decisions about them are," said Claisse. "The goal of the forum was to bring people together and get current information out there including experiences from other countries in decommissioning. The state and federal agencies really want the public and the stakeholders like recreational and commercial fisherman in California to be informed so that they are able to make their opinions known as this process moves forward."
Last fall, Claisse was the co-author of four papers published in the Bulletin of Marine Science that looked at how the patterns of fish abundance and reproductive output relate to various parts (depths) of the submerged platform structure, and how that compares to what is found on natural rocky reefs. Two of his graduate students, Chelsea Williams and Alex Roeper, served as co-authors on two of the papers. That research was funded in part by the USC Sea Grant program and the U.S. Bureau of Ocean Energy Management.
Claisse's current research focuses on natural and manmade reef ecosystems, habitat restoration and fisheries ecology. He and his students are involved in a project surveying kelp forests both inside and outside marine protected areas with the Vantuna Research Group, where he serves as associate director. They are also working on the habitat restoration of a kelp forest reef off the coast of Palos Verdes, which should be constructed this summer.
Photo credit: Jonathan Williams, Research Scientist (Vantuna Research Group, Occidental College)