Clinicopathological findings in sea turtles assessed during the Deepwater Horizon oil spill response

Abstract

During the BP Deepwater Horizon (DWH) oil spill in 2010, 319 live oiled sea turtles were rescued and admitted to rehabilitation centers for decontamination and veterinary care. Most turtles were small, surfaceñpelagic juveniles that were collected from oiled habitat distant from shore. Serial hematology, plasma biochemistry, and blood gas analyses were reviewed to characterize abnormalities relative to observed degree of oiling. Clinicopathological abnormalities upon admission indicated acute, nonspecific metabolic and osmoregulatory derangements that were attributable to a combination of events including stress, exertion, physical exhaustion, and dehydration related to oiling, capture, and transport. Specific toxicological effects reported in other taxa were not observed. Initial point-of-care blood data from one rescue center were evaluated using clinical assessment of physiological status for all turtles of all species with available data for pH, pCO2, sodium, and potassium. In addition, a prognostic model that was specifically developed for cold-stunned Kempís ridley sea turtles Lepidochelys kempii was applied to oiled Kempís ridley turtles from one center. Thirty-six percent of oiled turtles were identified as physiologically deranged based on a clinical assessment of their physiological status, and 25% of oiled Kempís ridley sea turtles exceeded the mortality risk threshold of the prognostic model. These results indicate that the physiological derangements in these animals were relatively severe and clinically relevant. Based on observations during the DWH spill, adverse physiological effects in sea turtles may be an important consequence of stress, exertion, physical exhaustion, and dehydration secondary to oiling, capture, and transport.