Is the Deepwater Horizon oil spill of 2010 killing Gulf of Mexico dolphins?

Deepwater Horizon April 21, 2010. Image: United States Coast Guard

When the Deepwater Horizon exploded and collapsed in April 2010, it released of “an estimated 4.9 million barrels of oil into the northern Gulf of Mexico.” Fatal to 11 oil workers, injurious to others, and disruptive of the environment and fishing industry along the Louisiana and Mississippi coasts, the “largest accidental marine oil spill in the history of the petroleum industry” has for many of us, receded into the past. Its aftereffects, however, continue to reverberate and now pose a serious threat to dolphins in areas "that received heavy and prolonged oiling."  

According to a recent multicenter study published in Environmental Science & Technology, a “guarded” or “grave” prognosis has been given to 65% of the bottlenose dolphins studied in Barataria Bay, Lousiana. 

“The oil spill resulting from the explosion of the Deepwater Horizon drilling platform initiated immediate concern for marine wildlife, including common bottlenose dolphins in sensitive coastal habitats. To evaluate potential sublethal effects on dolphins, health assessments were conducted in Barataria Bay, Louisiana, an area that received heavy and prolonged oiling, and in a reference site, Sarasota Bay, Florida, where oil was not observed.” (emphasis added)

“Barataria Bay dolphins were 5 times more likely to have moderate–severe lung disease, generally characterized by significant alveolar interstitial syndrome, lung masses, and pulmonary consolidation. Of 29 dolphins evaluated from Barataria Bay, 48% were given a guarded or worse prognosis, and 17% were considered poor or grave, indicating that they were not expected to survive. Disease conditions in Barataria Bay dolphins were significantly greater in prevalence and severity than those in Sarasota Bay dolphins, as well as those previously reported in other wild dolphin populations. Many disease conditions observed in Barataria Bay dolphins are uncommon but consistent with petroleum hydrocarbon exposure and toxicity.” (emphasis added)

Source: Health of Common Bottlenose Dolphins (Tursiops truncatus) in Barataria Bay, Louisiana, Following the Deepwater Horizon Oil Spill

Related Article: Focus on Ocean’s Health as Dolphin Deaths Soar