The Deepwater Horizon oil spill marine mammal injury assessment

From 2010 to 2015, a team of scientists studied how the BP Deepwater Horizon (DWH) oil spill affected marine mammals inhabiting the northern Gulf of Mexico, as part of the DWH Natural Resource Damage Assessment process. The scientists conducted the assessment on behalf of the DWH co- Trustees, with the purpose of investigating whether marine mammals were exposed to DWH oil and what types of injuries they suffered as a result of the DWH oil exposure, and then quantifying those injuries to determine the appropriate amount of restoration required to offset the injuries. Photographs, aerial surveys, spatial analyses of the co- occurrence between surface slick and cetacean populations, and chemical fingerprinting of oiled and stranded carcasses all confirm that at least 15 cetacean species were exposed to the DWH surface slick. Cetaceans that encountered the slick likely inhaled, aspirated, ingested, and/or adsorbed oil. In this Theme Section, marine mammal biologists, statisticians, veterinarians, toxicologists, and epidemiologists describe and quantify the adverse effects of this oil exposure. Taken together, this combination of oil spill dynamics, veterinary assessments, pathological, spatial, and temporal analyses of stranded animals, stock identification techniques, population dynamics, and a broad set of coordinated modeling efforts is an unprecedented assessment of how a major oil spill impacted a large and complex marine mammal community and their connected habitats.