It’s been two years since the Deepwater Horizon oil spill dumped nearly 5 million barrels of crude oil into the Gulf of Mexico. We’ve examined some of the consequences of this event earlier, but reverberations from the ecological disaster continue to be felt.
Fishermen in the region are finding significant deformities in large proportions of their catch: eyeless shrimp, fish covered with lesions, missing appendages, and others. As Al Jazeera reports:
"What we found is a very clear, genome-wide signal, a very clear signal of exposure to the toxic components of oil that coincided with the timing and the locations of the oil," Whitehead told Al Jazeera during an interview in his lab.
According to Whitehead, the killifish is an important indicator species because they are the most abundant fish in the marshes, and are known to be the most important forage animal in their communities.
"That means that most of the large fish that we like to eat and that these are important fisheries for, actually feed on the killifish," he explained. "So if there were to be a big impact on those animals, then there would probably be a cascading effect throughout the food web. I can’t think of a worse animal to knock out of the food chain than the killifish."
But we may well be witnessing the beginnings of this worst-case scenario.
Whitehead is predicting that there could be reproductive impacts on the fish, and since the killifish is a "keystone" species in the food web of the marsh, "Impacts on those species are more than likely going to propagate out and effect other species. What this shows is a very direct link from exposure to DWH oil and a clear biological effect. And a clear biological effect that could translate to population level long-term consequences."
Back on shore, troubled by what he had been seeing, Keath Ladner met with officials from the US Food and Drug Administration and asked them to promise that the government would protect him from litigation if someone was made sick from eating his seafood.
"They wouldn’t do it," he said.
"I’m worried about the entire seafood industry of the Gulf being on the way out," he added grimly.
The article summarizes the findings of three scientists: Dr Darryl Felder (Department of Biology, University of Louisiana, Lafayette), Dr Jim Cowan (Louisiana State University’s Department of Oceanography and Coastal Sciences), and Dr Andrew Whitehead (Louisiana State University):
Felder: Studies carried out from January 2010 to present in BP’s Macondo well area. Found abnormalities in shrimp post-spill, whereas pre-spill found none.
Cowan: Studies carried out from Nov 2010-present, from west Louisiana to west Florida, from coast to 250km out. Found lesions/sores/infections in 20 species of fish, as many as 50 per cent fish in some samples impacted. Pre spill levels were 1/10 of one per cent of fish.
Whitehead: Species such as the Gulf Killifish, in and around the Gulf of Mexico, will continue to be subject to negative effects of the BP oil spill disaster of 2010. The Killifish, which researchers consider a good indicator of water quality in the Gulf of Mexico, is showing signs that the oil spill is having a negative impact on its health. Tracked killifish for the first four months after spill across oil-impacted areas of Louisiana and Mississippi.