Accidental Ecologist, Winter 2006

The accidental ecologists When the offshore oil and gas runs out and the oil industry packs up and goes home, it leaves an unintended and surprising ecological legacy. But not everyone is so enamoured with this newly discovered by-product of the oil rigs as George Steinbach, Executive Director of the California Artificial Reef Enhancement Program explains.

S

killed

and

experienced

engineers from some of the largest engineering firms in the

world designed and built the oil and gas platforms for offshore

California.

They did a good job,

because the resulting structures have withstood wind and wave for decades in water depths up to 1,200 feet. But while the designers focused intently on deck loads and sheer forces to build platforms for drilling and production, they inadvertently built structures ideally shaped and configured for fish and marine life.

As these platforms

approach the end of their producing lives, we are beginning to deal with these unintended consequences.

Almost

immediately after the California platforms were installed, the growth of marine life on and around

The edge Winter 2006

structures

was

unmistakable. Over the years, the underwater portions of the platforms became home to mature reef ecosystems of fishes and invertebrates. Some of the easily accessible platforms are popular destinations for recreational fishermen. Divers and underwater photographers are attracted to the structures by a variety and abundance of marine life that makes them the best dive sites in the State. The marine growth on the platform legs is so prolific that it requires periodic removal to maintain platform stability. The contractor who cleans the legs also collects the removed mussels and scallops for sale into the local restaurant trade.

Underwater home. From l-r: Greenspotted rockfish at bottom of Platform Grace; Starfish in shallow midwaters at Platform Holly; juvenile bocaccio at Platform Gilda; flag rockfish at bottom of Platform Grace; juvenile vermillion rockfish at Platform Gilda and juvenile yellowtail rockfish at Platform Irene.

8

the

The platforms received little attention from marine scientists until the US Geological Survey (USGS) funded a study in 1995 to determine the role they play in the marine environment, if any. Dr Milton Love of the Marine Science Institute, University of California at Santa Barbara assembled a small team and began to survey the fish populations on several of the platforms. His team traversed the entire vertical reach of the structures, using scuba diving equipment for the shallow portions and a two-person submarine to reach the bottoms. The results confirmed the anecdotal evidence of extensive marine life, and the surveys became annual events for Love and his team. The research data, collected in a consistent manner for 10

The inescapable fact is that the California platforms, as they currently exist, are extremely successful artificial reef structures that play an important ecological role in the marine environment.

consecutive years, provides a sound scientific basis for several conclusions now drawn by Love.

the prospect of killing billions of marine animals and destroying highly productive marine habitat.

Love surveyed fish populations on both platforms and nearby natural reef outcrops and found both to be dominated by rockfishes of genus Sebastes, a commercially important group of fishes on the Pacific Coast. The surveys show that, compared to natural reefs, the platforms have

The reaction of environmental groups to Love’s scientific evidence was revealing. Many dismissed the existence of marine life as of secondary importance to seeing the platforms

higher densities of juvenile rockfishes and are functionally more important as nurseries. Also, compared to natural reefs, the platforms have higher densities of reproducing-age adults and, therefore, contribute a higher proportion of rockfish larval production. Overall, Love has concluded that the platforms are not just passive attractors of fish, but play an important role in regional rockfish production. The inescapable fact is that the California platforms, as they currently exist, are extremely successful artificial reef structures that play an important ecological role in the marine environment.

removed. After all, the oil industry promised to remove them, and they should not be let ‘off the hook.’ The platforms are artificial and constitute ‘industrial junk.’ The removal of the platforms is needed ‘to produce a catharsis for all the damage caused by the oil industry.’ It became clear that the scientific evidence alone was going to fail in the face of these very humancentric views of what constitutes appropriate marine habitat. A separate advocacy group was going to be needed to make an argument for the fish.

fishermen, divers, Recreational scientists, environmentalists and fishermen have commercial volunteered to tell the story of these accidental reefs. By challenging the conventional wisdom of removing the oil platforms, a foregone conclusion has become a debate. The decommissioning of the platforms is now seen for its fisheries management implications. The discussion is heated, and the outcome is not certain. However, serious people are now asking the right question: ‘What is the best way to decommission California’s offshore platforms?’ For more information about the work of CARE visit the website: www.calreefs.org/

The California Artificial Reef Enhancement Program (CARE) was founded as a non-profit organisation in 1999. It represents a broad constituency of ocean users who believe that the platforms are valuable habitat and that alternatives to fullremoval should be considered.

Credits

When these platforms run out of oil and gas, the oil industry has a clear obligation to remove the structures. Many environmentalist groups, especially those that oppose the oil industry, have been looking forward to this end to the industry’s presence offshore. However, these groups are now faced with another consequence both unforeseen and unsavory. The removal of the platforms also means the removal of the accidental reefs, and

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