Some red snapper caught in the area of the oil spill have severe fin rot, particularly on their anal fins. A healthy fish would be able to fight off such infections, scientists say. They suspect that the immune systems have collapsed as a result of a toxin.
A year after the Deepwater Horizon disaster spewed oil into the Gulf of Mexico, the Florida beaches are relatively clean, the surf seems clear, and the tourists are returning. But there are signs that the disaster is continuing to affect marine life in the Gulf far from where humans can observe it.
Over the winter, anglers who had been working the Gulf for decades began hauling in red snapper that didn’t look like anything they had seen before. The fish had dark lesions on their skin, some the size of a 50-cent piece. On some of them, the lesions had eaten a hole straight through to the muscle tissue. Many had fins that were rotting away and discolored or even striped skin. Inside, they had enlarged livers, gallbladders, and bile ducts.
“The fish have a bacterial infection and a parasite infection that’s consistent with a compromised immune system,” said Jim Cowan, an oceanographer at Louisiana State University, who has been examining them. “There’s no doubt it’s associated with a chronic exposure to a toxin.”
He believes the toxin in question is oil, given where and when the fish were caught, their symptoms, and the similarity to other incidents involving oil spills. But he is awaiting toxicology tests to be certain.
Cowan said he hasn’t seen anything like these fish in 25 years of studying the Gulf, which persuades him that “it would be a pretty big coincidence if it wasn’t associated with the oil spill.”
If he were a detective, he’d be ready to make an arrest. “It’s a circumstantial case,” he said, “but at the same time I think we can get a conviction.”
Red snapper are reef fish that feed on mantis shrimp, swimming crabs, and other small creatures found in the sediment on the Gulf floor. Anglers catch them at anywhere from 60 to 200 feet deep. In addition to the snapper, some sheepshead have turned up with similar symptoms, Cowan said.
The fish with lesions and other woes have been caught anywhere from 10 to 80 miles offshore between Pensacola and the mouth of the Mississippi River, an area hit hard by last year’s oil spill, Cowan said.
“They’re finding them out near the shelf edge, near the spill site,” said Will Patterson, a marine biology professor at the University of West Florida.
Patterson, who has been studying reef fish in the Gulf for past two years, has sent some of the strange catches to a laboratory for toxicology tests. He suspects Cowan is correct about the oil being the culprit but is withholding judgment.
Red snapper are a popular seafood, with a delicate sweet flavor whether served broiled, baked, steamed, poached, fried, or grilled. Asked whether the sick fish might pose a hazard to humans who ate them, Cowan said nobody would want to touch these, much less cook them.
“It’s pretty nasty,” Cowan said. “If you saw this, you wouldn’t eat it.”
Most of the fishermen who caught the weird snappers tossed them back, weighed anchor and moved to another spot, he said. But a few dropped their suspect catch into a box separate from the healthy fish and brought them to shore to show to scientists.
Several of those scientists discussed the disquieting discovery at a conference at the University of South Florida in St. Petersburg recently.
“We’re seeing fish anomalies, strange-looking fish,” said Richard Snyder, Director of the Center for Environmental Diagnostics and Bioremediation at the University of West Florida, who has accompanied fishermen going out to collect samples for study. “Wound-healing is becoming an issue.”
The key is what happened to the livers and bile, said Ernst Peebles of the University of South Florida, who is far more cautious about attributing the lesions and discoloration to the spill because they could be caused by something else.
The liver, gallbladder, and bile system filter out hydrocarbons — oil components — that the fish might consume while eating their prey. If those systems are enlarged, that means they have become stressed out. That, Peebles said, “is very consistent with the impacts of oil.”
If those systems quit working, that would compromise the immune system, Cowan said.
Does that mean the crustaceans and other prey that the red snapper have been eating are contaminated with oil? “I don’t think anybody’s looked,” said Cowan.
However, University of South Florida scientists have found some microscopic organisms called “foraminifera” — forams, for short — that are also showing signs that something troubling is going on in the Gulf. Forams live on the Gulf bottom and are eaten by worms, crustaceans, and fish.
Ben Flower of USF said they have found forams in the Gulf “with deformed shells. . . . It was striking.” There is evidence of hydrocarbons from oil in the sediment, but test results that could show if that’s the cause of the deformity are still in the works, he said.
The symptoms displayed by the red snapper are similar to something that happened four years after the 1989 Exxon Valdez spill in Alaska. In 1993 the herring fishery in Prince William Sound crashed. The herring succumbed to fungus and a virus — their immune systems had been compromised.
However, a 1999 report noted that “the extent to which the exposure to oil contributed to the 1993 disease outbreak is uncertain.”
Gil McRae, Director of the state’s Marine Science Laboratory in St. Petersburg, said he thought it was “irresponsible” for scientists to be attributing the red snapper’s symptoms to the spill without further testing and analysis.
All of the scientists involved said they were nervous about what impact this might have on the Gulf’s seafood industry, which still has not recovered from the shutdowns and bad publicity during last year’s crisis. Peebles pointed out that any premature release of information could also scare fishermen away from helping the scientists investigate what was going on.
“Now we’re hiding information because political and economic interests don’t want you to say anything because it would affect economic interests,” said William “Bill” Hogarth, a former federal fisheries official who now oversees the Florida Institute of Oceanography. “But fishermen, they’re seeing fish that are deformed.”
Craig Pittman can be reached at firstname.lastname@example.org.