Lesions of Gulf of Mexico Fish Linked to Oil Spill

Skin lesions found on large a number of fish in the northern Gulf of Mexico have been linked to the 2010 Deepwater Horizon (DWH) ocean spill, scientists from the University of South Florida (USF) say.

Published in the journal Transactions of the American Fisheries Society, USF scientists reported a strong resemblance between oil from the Deepwater blowout and an outbreak of skin lesions and oil residue signatures discovered in bottom-dwelling fish, like the red snapper, a year after the spill.

"The higher rates of skin lesions in 2011 versus 2012 were not due to an outbreak of pathogens or abnormally low salinity, and thus the hypothesis that DWH was responsible for the higher rates of skin lesions remains viable," researcher Steven Murawski, a professor of population dynamics and marine ecosystem analysis at USF's College of Marine Science, said in a news release.

The spill was the result of an explosion on April 20, 2010, and released an estimated 4.9 million barrels of oil into the waters. The amount of oil was so large that it spread to more than thousands of square miles from the rig's location off New Orleans to the west coast of Florida, Uncover California reported.

Fishermen from the northern Gulf had reported abnormal looking fish beginning in the winter of 2010-2011, and so scientists set out to investigate the issue.

"Surveys revealed that by 2012 the overall lesion frequency had declined 53 percent, with the severity of lesions also declining," the authors noted in the release.

Researchers dissected livers of some of the fish sampled in 2011 and found the bile having relatively high concentrations of a hydrocarbon. It was clear indication for the researchers that it was related to oil-linked pollution.

However, they found huge decline in these concentrations between 2011 and 2012, which led scientists to believe that the exposure was restricted to single episode.

Work by the group of scientists continues in order to better understand the implications of the exposure to Deepwater Horizon oil on the growth, reproduction and survival of fishes that were affected by the spill.