Lesions on the skin of fish living in the Gulf of Mexico can be traced to the Deepwater Horizon oil spill, according to new research.
Steven Murawski began studying fish in the Gulf when after fishermen reported seeing a large number of the animals suffering from lesions. The skin disorders started appearing in 2010 and became more common in 2011.
The Deepwater Horizon oil spill started on 20 April 2010, when the Deepwater Horizon oil rig exploded, taking the lives of 11 people. It is widely considered to be the largest accidental marine oil spill in history. A 2014 study showed life-threatening deformities to the hearts and other vital organs of tuna and amberjack.
University of South Florida (USF) researchers, working with scientists from the Florida Institute of Oceanography (FIO) and the Florida Fish and Wildlife Research Institute (FWRI), performed examination of the animals. They found livers and muscle tissues in the fish contained chemicals similar to those released in the spill. Pathogens and water conditions were eliminated as possible causes of the disorders.
"The higher rates of skin lesions in 2011 vs. 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," Steven Murawski, a professor of population dynamics and marine ecosystem analysis at USF, said.
Lesions were most common in bottom-dwelling fish, living on the continental shelf of the northern Gulf region. The massive oil spill happened just south of the are suffering the greatest damage.
Polycyclic aromatic hydrocarbons, or PAHs, are among the most toxic, and carcinogenic, components of crude oil. The team showed elevated levels of this substance in fish recovered from the area. These concentration went down by 50 percent in 2012, providing evidence the spill was responsible for the presence of the chemical.
In 2012, the number of lesions reduced by 53 percent, and the severity of the wounds present was lessened.
Future research will continue to examine marine life in the Gulf, striving to understand how the oil spill affected fish and other wildlife.
Investigation of lesions in fish found in the Gulf of Mexico and their possible ties to the Deepwater Horizon oil spill was profiled in the journal Transactions of the American Fisheries Society.
