Oil that matches the 2010 Deepwater Horizon spill in the Gulf of Mexico has been found in the bodies of sickened fish, according to a team of Florida scientists who studied the oil's chemical composition.

"We matched up the oil in the livers and flesh with Deepwater Horizon like a fingerprint," said lead researcher Steven Murawski, a professor at the University of South Florida's College of Marine Science in Tampa.

He said the findings debunk arguments that fish abnormalities could have been caused by other factors including oil in coastal runoff and oil from naturally occurring seeps in the Gulf of Mexico.