Deepwater Horizon oil spill still impacts bottlenose dolphins

The author assists Dr. Cynthia Smith, principal investigator for the Deepwater Horizon marine mammal impact project and lead veterinarian/executive director for the National Marine Mammal Foundation, on a dolphin health assessment in Barataria Bay, Louisiana. PHOTO: © NOAA National Marine Fisheries ServiceThis week marks the anniversary of the catastrophic Deepwater Horizon oil spill in the Gulf of Mexico that began on the evening of April 20, 2010. While it has been seven years since the spill, its effects are still resonating within the ecosystem, and scientists continue the hard work of investigating long-lasting impacts on the affected animals and habitat.

One area of study of particular interest to IFAW’s Marine Mammal Rescue and Research team is evaluating the health of bottlenose dolphin populations living in one of the most heavily oiled locations—Barataria Bay, Louisiana.

IFAW became involved with this project in 2013 when our staff served as part of the team performing health assessments on the coastal Barataria Bay dolphins. This project brought together marine mammal experts across state and federal agencies to non-governmental organizations with the common goal to evaluate the long-term effects of an unprecedented human-caused disaster in the marine environment.

Since 2013, several members of our team have traveled down to Louisiana and Mississippi to participate in these health assessments under the direction of the National Marine Mammal Foundation, NOAA National Marine Fisheries Service and several other prominent scientific agencies.

Through these efforts, the research team has found that dolphins in Barataria Bay exhibited moderate to severe lung disease and insufficient stress response with low levels of cortisol up to four years following the spill. Reproductive rates were also lower in this population in the years following the spill, with increased calf deaths and known pregnant dolphins later being seen without their expected calves.

At the current rate, estimates suggest that it may take up to 40 years for the population to fully recover from this event.

The health assessments being conducted in Barataria Bay are also being adapted to help detect lung and reproductive diseases in stranded dolphins here on Cape Cod, and these diagnostic advancements will hopefully be brought to other parts of the world in the near future. IFAW is honored and committed to continuing this important work. 

A portion of the team’s findings were released in the Inter-Research journal Endangered Species Research. Read the full text here.


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