TAMPA — A team of local researchers has found strong evidence that skin lesions discovered on fish in the northern Gulf of Mexico were related to the Deepwater Horizon oil spill.
Scientists from the University of South Florida, the Florida Institute of Oceanography and the Florida Fish and Wildlife Research Institute ruled out pathogens and oceanographic conditions as causes of the lesions, and they also said that a toxic component of the type of crude oil released by the Deepwater Horizon blowout was found in fish liver and muscle.
“These kinds of findings support the concept that these (events) have a long-term and significant ecological impact,” said David Hollander, a USF professor involved with the project.
BP’s Deepwater Horizon rig exploded in April 2010, killing 11 workers and spewing more than 200 million gallons of oil into the Gulf by the time the wellhead could be capped almost three months later. By the winter of 2010-11, fishermen were reporting abnormal-looking fish.
The St. Petersburg-based researchers said they found elevated levels of an oil compound called polycyclic aromatic hydrocarbons, or PAHs, in bottom-dwelling fish such as red snapper near the site. There was a strong resemblance — a “carbon copy,” according to Hollander — of the oil found in the fish to the oil released by the Deepwater Horizon blowout.
Overall lesion frequency declined 53 percent from 2011 to 2012, with the severity of the lesions also declining, the scientists said. PAH residues in snapper bile declined over that year by up to 50 percent.
That indicates that the fish were exposed to an episodic pollution event, the researchers said, as opposed to pathogens, low salinity or regularly occurring oil seepage, they said.
The group’s findings were published last week in Transactions of the American Fisheries Society. The team of scientists and graduate students was led by Steven Murawski, a professor of population dynamics and marine ecosystem analysis at USF’s College of Marine Science. The paper was co-authored by the oceanography institute’s William Hogarth, USF’s Ernst Peebles and the wildlife institute’s Luiz Barbeiri.