Retired oil rigs off the California coast could find new lives as artificial reefs

Offshore oil and gas drilling has been a contentious issue in California for 50 years, ever since a rig ruptured and spilled 80,000 to 100,000 barrels of crude oil off Santa Barbara in 1969. Today it’s spurring a new debate: whether to completely dismantle 27 oil and gas platforms scattered along the southern California coast as they end their working lives, or convert the underwater sections into permanent artificial reefs for marine life.

We know that here and elsewhere, many thousands of fishes and millions of invertebrates use offshore rigs as marine habitat. Working with state fisheries agencies, energy companies have converted decommissioned oil and gas platforms into manmade reefs in the U.S. Gulf of Mexico, Brunei and Malaysia.

Californians prize their spectacular coastline, and there are disagreements over the rigs-to-reefs concept. Some conservation groups assert that abandoned oil rigs could release toxic chemicals into the water and create underwater hazards. In contrast, supporters say the submerged sections have become productive reefs that should be left in place.

We are a former research scientist for the U.S. Department of the Interior and a scholar focusing on the fishes of the Pacific coast. In a recent study, we reviewed the history of rigs-to-reefs conversions and decades of published scientific research monitoring the effects of these projects. Based on this record, we conclude that reefing the habitat under decommissioned oil and gas platforms is a viable option for California. It also could serve as a model for decommissioning some of the 7,500 other offshore platforms operating around the world.

[embedded content] Reefing oil rigs clearly benefits oil companies, but scientists say it’s also good for marine life.

Unplanned underwater communities

Offshore petroleum platforms are designed to withstand hurricanes and earthquakes, but not to be permanent. When they reach the end of their useful lives, typically after about 25 to 50 years of operation, federal and state law require energy companies to decommission them.

This usually means completely removing the platform and submerged supporting structure and returning the seafloor to an unobstructed condition. Only in certain cases does any part of the platform remain.

These rigs weren’t designed with the intent of creating reefs, but their underwater steel pipe support systems – called “jackets” in the oil business – attract vast numbers of invertebrates that settle on them. In turn, these creatures attract diverse fish species. Together these colonies create reef systems that can resist rusting away for several hundred years.

Off California, a myriad of invertebrates coat each platform jacket. Millions of mussels, sea stars and brightly colored anemones fight for space, creating a quilt of patterns and textures. Both large and small fishes are also abundant. In some years, clouds of hundreds of thousands of juvenile rockfishes school in the depths below operating oil platforms.

Creating new habitat

Humans have sought to enhance fisheries with artificial reefs for centuries, using materials ranging from wood, rock and concrete to decommissioned ships. The idea of reefing platform jackets developed after oil and gas companies started building platforms in the Gulf of Mexico in the late 1940s. Those steel-pipe structures provided rock-hard habitat for reef fishes on an otherwise smooth seafloor, and became highly popular fishing destinations.

Installing thousands of platforms catalyzed a basin-wide increase in available reef fish species, such as the highly prized red snapper. Reef fishes moved into areas where they had previously been scarce due to a lack of hard habitat.