Barataria Bay - Open sores. Parasitic infections. Chewed-up-looking fins. Gashes. Mysterious black streaks. Two years after the drilling-rig explosion that touched off the biggest offshore oil spill in US history, scientists are beginning to suspect that fish in the Gulf of Mexico are suffering the effects of the petroleum.
The evidence is nowhere near conclusive. But if those suspicions prove correct, it could mean that the environmental damage to the Gulf from the BP disaster is still unfolding and the picture isn't as rosy as it might have seemed just a year ago.
And the damage may extend well beyond fish. In the past year, research has emerged showing deep-water coral, seaweed beds, dolphins, mangroves and other species of plants and animals are suffering.
"There is lots of circumstantial evidence that something is still awry," said Christopher D'Elia, dean of Louisiana State University's School of the Coast and Environment. "On the whole, it is not as much environmental damage as originally projected. Doesn't mean there is none."
Reports of strange things with fish began emerging when fishermen returned to the Gulf weeks after BP's gushing oil well was capped during the summer of 2010. They started catching grouper and red snapper with large open sores and strange black streaks, lesions they said they had never seen. They promptly blamed the spill.
The illnesses are not believed to pose any health threat to humans. But the problems could be devastating to some prized types of fish and to the people who make their living catching them.
There's no saying for sure what's causing the diseases in what is still a relatively small percentage of the fish. The Gulf is assaulted with all kinds of contaminants every day. Moreover, scientists have no baseline data on sick fish in the Gulf from before the spill. The first comprehensive research may be years from publication.
Still, it's clear to fishermen and researchers alike that something's amiss.
- A recent batch of test results revealed the presence of oil in the bile extracted from fish caught in August 2011, nearly 15 months after the well blew out on April 20, 2010, in a disaster that killed 11 men.
"Bile tells you what a fish's last meal was," said Steve Murawski, a marine biologist with the University of South Florida and former chief science adviser for the National Marine Fisheries Service. "There was as late as August of last year an oil source out there that some of those animals were consuming."
Bile in red snapper, yellow-edge grouper and a few other species contained on average 125 parts per million of naphthalene, a compound in crude oil, Murawski said. Scientists expect to find almost none of the substance in fish captured in the open ocean.
- Last year, a federally funded team of scientists conducted what experts say is the most extensive study yet of sick fish in shallow and deep Gulf waters. Over seven cruises in July and August, the scientists caught about 4 000 fish, from Florida's Dry Tortugas to Louisiana.
About 3% of the fish had gashes, ulcers and parasites symptomatic of environmental contamination, according to Murawski, the lead researcher.
The number of sick fish rose as scientists moved west away from the relatively clean waters of Florida, and also as they pushed into deeper waters off Alabama, Mississippi and especially Louisiana, near where the Deepwater Horizon rig sank.
About 10% of mud-dwelling tile fish caught in the DeSoto Canyon, to the northeast of the well, showed signs of sickness.
"The closer to the oil rig, the higher the frequency was" of sick fish, Murawski said.
Past studies off the Atlantic Seaboard found about 1% of fish suffering from diseases, Murawski said. But he said that figure cannot really be used for comparisons with the Gulf, whose warmer waters serve as an incubator for bacteria and parasites that can cause lesions and other illnesses.
- Laboratory work over the past winter on the USF samples indicates the immune systems of the fish were impaired by an unknown environmental stress or contamination. Other researchers say they have come to similar conclusions.
"Some of the things I've seen over the past year or so I've never seen before," said Will Patterson, a marine biologist at the University of South Alabama and at the Dauphin Island Sea Lab. "Things like fin rot, large open sores on fish, those were some of the more disturbing types of things we saw. Different changes in pigment, red snapper with large black streaks on them."
Teasing out what might have been caused by the spill and what is normal will be tricky, and that's the challenge scientists now face. Deformities, diseases and sudden shifts in fish numbers are regular occurrences in nature. For example, scientists are not sure what to make of reports from fishermen of eyeless or otherwise deformed shrimp and crabs.
"I've heard everything but shrimp with two heads," said Jerald Horst, a marine biologist retired from LSU AgCenter who writes books about the Gulf. "I listen respectfully. Reports can be useful but are not proof in themselves of cause and effect."
Even if oil were pinpointed as the cause, it could be difficult to definitively tie the problem to the BP spill. The Gulf is strewn with wells, pipelines, natural oil leaks from the seafloor, and pollution from passing ships. And muddy, contaminant-laden water flows constantly into the Gulf from the Mississippi River.
Still, the more scientists look - thanks to millions of dollars in research money, much of it coming from a fund set up by BP for independent research - the more they're finding that may be off-kilter.