SCIENTISTS studying lesions found on the skin of fish in the Gulf of Mexico in 2011 and 2012 have not ruled out toxic chemicals contained in oil released during the BP Deepwater Horizon oil spill as the cause.
A report in nola.com highlights a peer-reviewed study released yesterday, which suggests that there is no proof that the oil spill did cause the lesions, there is no evidence to say that it did not.
‘We can’t say with 100 per cent certainty that it was the Deepwater Horizon oil spill’, explained Steven Murawski, marine science professor at the University of South Florida, ‘but we can say what it wasn’t.
‘We’ve analyzed the other potential sources and the one that correlates the best is the Deepwater Horizon, he added.
The findings, published in Transactions of the American Fisheries Society, were disputed by BP. According to Geoff Morrell, a senior vice president with BP, such lesions ‘have long been observed in the Gulf and have little effect on a species’ health or population.’
He added that in the past the lesions have been linked to agricultural and industrial activities along the Gulf, as well as a number of other factors.
‘In addition, the study ignores and runs counter to data from thousands of water samples that show that the PAH exposure levels were too low to have significantly increased the incidence of fish lesions’, he continued.
‘Despite these and other shortfalls, the researchers themselves still admit ‘we cannot definitively link cause and effect using only two years of post-event data.’
The study evaluated 7,433 fin fish (103 species caught at 150 sampling stations) in 2011 and 2012, and discovered that the rates of lesions varied widely with species, area and depth.
Interestingly, the paper noted significant declines in two metabolites – naphthalene and phenanthrene – were found in red snapper between 2011 and 2012, which suggests that the exposure was episodic, rather than continuous or chronic.
‘The Gulf is full of oil wells and seeps, and if these were due to continuous exposure (from those other sources), we wouldn’t see a 50 per cent statistically significant drop in these fish,’ said the report.
The study was funded by National Marine Fisheries Service and NOAA, The Louisiana Oil Spill Coordinator’s Office and the BP-Gulf of Mexico Research Initiative.