A new study from UCSB marine biologists found how different ways to decommission offshore oil platforms affect the surrounding fish biomass, in hopes of preserving the number of fish and encouraging the best environmental decisions for government agencies.
Because platforms serve as de facto habitats for the fish, the full removal of oil platforms could potentially kill or displace a large amount of fish biomass, according to the study. In addition, the site would eventually return to mud, which is a more challenging home for fish to inhabit.
The research concluded that completely removing a platform could reduce fish biomass by 95 percent, while only removing the top of the rig reduces biomass by 10 percent — a significant difference. If just the part above water is removed, most of the fish and the habitat will remain, and only fresh mussels growing on the top would fall to the seafloor.
As a UCSB postdoctoral scholar and the lead author of the paper, Erin Meyer-Gutbrod’s research aims to assist the state agencies in making the best decision in decommissioning these platforms.
“I do think that the partial removal option is both possible and realistic,” she said, citing more than 500 offshore platforms in the Gulf of Mexico with only their tops removed to preserve artificial reefs. “Partial removal not only preserves the fish currently living on the deeper parts of the structure, but those fish are also able to continue reproducing, adding to future fish generations. There can also be substantial cost savings to oil and gas companies, and these savings are split with the state and can be applied to natural resources and conservation.”
She added that there are many other factors to consider while decommissioning these platforms, such as the potential release of toxins when dredging the shell mound, the removal’s carbon footprint and waste generation.
“There is also a diverse range of stakeholders, including commercial trawlers, anglers, divers, tourism, etc., with different perspectives on the value of the existing platform or, conversely, a return to an unobstructed seabed,” Ms. Meyer-Gutbrod said. “All of these concerns must be weighed to make the best decommissioning decisions.”
Ms. Meyer-Gutbrod’s work has been funded by the Bureau of Ocean Energy Management. Bob Miller and Milton Love co authored the study, which can be found in the journal “Ecological Applications.”