New Orleans, LA - "The fishermen have never seen anything like this," Dr Jim Cowan told Al Jazeera. "And in my 20 years working on red snapper, looking at somewhere between 20 and 30,000 fish, I've never seen anything like this either."

Dr Cowan, with Louisiana State University's Department of Oceanography and Coastal Sciences started hearing about fish with sores and lesions from fishermen in November 2010.

Cowan's findings replicate those of others living along vast areas of the Gulf Coast that have been impacted by BP's oil and dispersants.

Gulf of Mexico fishermen, scientists and seafood processors have told Al Jazeera they are finding disturbing numbers of mutated shrimp, crab and fish that they believe are deformed by chemicals released during BP's 2010 oil disaster.

Along with collapsing fisheries, signs of malignant impact on the regional ecosystem are ominous: horribly mutated shrimp, fish with oozing sores, underdeveloped blue crabs lacking claws, eyeless crabs and shrimp - and interviewees' fingers point towards BP's oil pollution disaster as being the cause.

Eyeless shrimp

Tracy Kuhns and her husband Mike Roberts, commercial fishers from Barataria, Louisiana, are finding eyeless shrimp.

"At the height of the last white shrimp season, in September, one of our friends caught 400 pounds of these," Kuhns told Al Jazeera while showing a sample of the eyeless shrimp.

According to Kuhns, at least 50 per cent of the shrimp caught in that period in Barataria Bay, a popular shrimping area that was heavily impacted by BP's oil and dispersants, were eyeless. Kuhns added: "Disturbingly, not only do the shrimp lack eyes, they even lack eye sockets."

Eyeless shrimp, from a catch of 400 pounds of eyeless shrimp, said to be caught September 22, 2011, in Barataria Bay, Louisiana [Erika Blumenfeld/Al Jazeera]

"Some shrimpers are catching these out in the open Gulf [of Mexico]," she added, "They are also catching them in Alabama and Mississippi. We are also finding eyeless crabs, crabs with their shells soft instead of hard, full grown crabs that are one-fifth their normal size, clawless crabs, and crabs with shells that don't have their usual spikes … they look like they've been burned off by chemicals."

On April 20, 2010, BP's Deepwater Horizon oilrig exploded, and began the release of at least 4.9 million barrels of oil. BP then used at least 1.9 million gallons of toxic Corexit dispersants to sink the oil.

Keath Ladner, a third generation seafood processor in Hancock County, Mississippi, is also disturbed by what he is seeing.

"I've seen the brown shrimp catch drop by two-thirds, and so far the white shrimp have been wiped out," Ladner told Al Jazeera. "The shrimp are immune compromised. We are finding shrimp with tumors on their heads, and are seeing this everyday."

While on a shrimp boat in Mobile Bay with Sidney Schwartz, the fourth-generation fisherman said that he had seen shrimp with defects on their gills, and "their shells missing around their gills and head".

"We've fished here all our lives and have never seen anything like this," he added.

Ladner has also seen crates of blue crabs, all of which were lacking at least one of their claws.

Darla Rooks, a lifelong fisherperson from Port Sulfur, Louisiana, told Al Jazeera she is finding crabs "with holes in their shells, shells with all the points burned off so all the spikes on their shells and claws are gone, misshapen shells, and crabs that are dying from within … they are still alive, but you open them up and they smell like they've been dead for a week".

Rooks is also finding eyeless shrimp, shrimp with abnormal growths, female shrimp with their babies still attached to them, and shrimp with oiled gills.

"We also seeing eyeless fish, and fish lacking even eye-sockets, and fish with lesions, fish without covers over their gills, and others with large pink masses hanging off their eyes and gills."

Rooks, who grew up fishing with her parents, said she had never seen such things in these waters, and her seafood catch last year was "ten per cent what it normally is".

"I've never seen this," he said, a statement Al Jazeera heard from every scientist, fisherman, and seafood processor we spoke with about the seafood deformities.

Given that the Gulf of Mexico provides more than 40 per cent of all the seafood caught in the continental US, this phenomenon does not bode well for the region, or the country.

BP's chemicals?

"The dispersants used in BP's draconian experiment contain solvents, such as petroleum distillates and 2-butoxyethanol. Solvents dissolve oil, grease, and rubber," Dr Riki Ott, a toxicologist, marine biologist and Exxon Valdez survivor told Al Jazeera. "It should be no surprise that solvents are also notoriously toxic to people, something the medical community has long known".

The dispersants are known to be mutagenic, a disturbing fact that could be evidenced in the seafood deformities. Shrimp, for example, have a life-cycle short enough that two to three generations have existed since BP's disaster began, giving the chemicals time to enter the genome.

Pathways of exposure to the dispersants are inhalation, ingestion, skin, and eye contact. Health impacts can include headaches, vomiting, diarrhea, abdominal pains, chest pains, respiratory system damage, skin sensitisation, hypertension, central nervous system depression, neurotoxic effects, cardiac arrhythmia and cardiovascular damage. They are also teratogenic - able to disturb the growth and development of an embryo or fetus - and carcinogenic.

Cowan believes chemicals named polycyclic aromatic hydrocarbons (PAHs), released from BP's submerged oil, are likely to blame for what he is finding, due to the fact that the fish with lesions he is finding are from "a wide spatial distribution that is spatially coordinated with oil from the Deepwater Horizon, both surface oil and subsurface oil. A lot of the oil that impacted Louisiana was also in subsurface plumes, and we think there is a lot of it remaining on the seafloor".

Dr Wilma Subra, a chemist and Macarthur Fellow, has conducted tests on seafood and sediment samples along the Gulf for chemicals present in BP's crude oil and toxic dispersants.

"Tests have shown significant levels of oil pollution in oysters and crabs along the Louisiana coastline," Subra told Al Jazeera. "We have also found high levels of hydrocarbons in the soil and vegetation."

According to the US Environmental Protection Agency, PAHs "are a group of semi-volatile organic compounds that are present in crude oil that has spent time in the ocean and eventually reaches shore, and can be formed when oil is burned".

"The fish are being exposed to PAHs, and I was able to find several references that list the same symptoms in fish after the Exxon Valdez spill, as well as other lab experiments," explained Cowan. "There was also a paper published by some LSU scientists that PAH exposure has effects on the genome."

The University of South Florida released the results of a survey whose findings corresponded with Cowan's: a two to five per cent infection rate in the same oil impact areas, and not just with red snapper, but with more than 20 species of fish with lesions. In many locations, 20 per cent of the fish had lesions, and later sampling expeditions found areas where, alarmingly, 50 per cent of the fish had them.

"I asked a NOAA [National Oceanic and Atmospheric Administration] sampler what percentage of fish they find with sores prior to 2010, and it's one tenth of one percent," Cowan said. "Which is what we found prior to 2010 as well. But nothing like we've seen with these secondary infections and at this high of rate since the spill."

"What we think is that it's attributable to chronic exposure to PAHs released in the process of weathering of oil on the seafloor," Cowan said. "There's no other thing we can use to explain this phenomenon. We've never seen anything like this before."

Official response

Questions raised by Al Jazeera's investigation remain largely unanswered.

Al Jazeera contacted the office of Louisiana governor Bobby Jindal, who provided a statement that said the state continues to test its waters for oil and dispersants, and that it is testing for PAHs.