The BP oil spill caused skin lesions in fish, according to USF scientists.
Researchers started sailing to the northern Gulf in 2011, nearly a year after the Deepwater Horizon disaster.
They caught hundreds of fish to determine the impact on marine life. That's when researchers first noticed the skin lesions.
"The first year, 2011, we had a relatively high rate of infection rate in skin lesions," said USF researcher Steve Murawski.
The following year, researchers noticed fewer skin lesions. Murawski said it's likely because the problems began from a catastrophic event, the 2010 oil spill.
"By following these fish over time, we can see that the levels are declining back to probably what is a more normal condition," Murawski said.
Researchers also discovered high oil concentrations inside the fish. They believed that oil came from the spill as well.
The findings were published in the online publication, Transactions of the American Fisheries Society.
The research was funded through an $11 million grant from the Gulf of Mexico Initiative.
Meanwhile, this is just the beginning for researchers. They're still conducting a study to determine whether the spill caused fish to grow at a slower rate.
The USF team will return to the Gulf to continue their research next month.