Imagine a school of fish in the Gulf of Mexico, swimming aimlessly through the murky seawater, suddenly plummeting through a wall of brown, sludgy oil.
Professors at the University of South Florida’s Marine Science Department wish it were that simple to see.
Chemical oceanography professor David Hollander said much of the oil spill damage has yet to be seen.
“A lot of people imagine birds struggling to fly because they are drenched in tar or black oil,” he said. “But it’s really nothing like that at all. Scientists are now dealing with invisible oil.”
Yet, biological oceanography professor Steven Murawski said diagnosing a problem in the Gulf of Mexico is more complicated than it appears to be.
“People are forgetting this is science we are dealing with,” Murawski said. “Everyone wants answers, but there may never be an answer.”
Murawski designed an expansive survey to study the fish that were expected to be diseased as a result of the oil spill.
“The study covers about 500 miles of the eastern Gulf,” he said. “We have a fishing line about five miles longs with 50,000 hooks attached.”
Ernst Peebles, a biological oceanography professor and a colleague of Murawski, said the study was the largest scale fish survey ever performed.
Peebles and his lab investigate the age of fish with ulcers or lesions in areas both near and far from the spill’s source.
“My group takes a forensic approach to unlock codes located in fish,” he said. “We can examine otolith or ear bone by using laser technology to correspond age with time. We can count ear rings, like tree rings, to reveal the ages of the fish.”
Peebles said laser technology can detect 24 different elements located in the ear bones of the fish. Nickel and vanadium, elements not native to the Gulf of Mexico ecology, are often seen in the bones of fish near the oil spill origin, he said.
“Once we have this information we investigate if the minerals correspond with the ear bone at the time of the spill. We have a few, but not enough, fish that match these exact dates.”
“Finding out if these fish are sick as a result of the oil spill seems to be the billion-dollar question,” Murawski said,” he said. “Some fishermen have actually noticed a change in the fish and some have not.”
Murawski said the survey is far from providing answers, but rather is providing a place from which to start looking for them.
“We have considerable evidence, but we can’t make conclusions until enough data is taken,” he said. “We need to rule out as much as we can.”