Abstract

On April 20, 2010 the offshore oil rig Deepwater Horizon exploded off the Louisiana coast resulting in the spillage of several hundred million gallons of oil into the Gulf of Mexico. Federal and state wildlife officials recovered over 450 live oiled sea turtles in the ensuing months which were transported to primary care facilities in Louisiana, Mississippi and Florida. The Audubon Nature Institute in New Orleans, Louisiana received 187 oiled Kemps Ridley, Green, Loggerhead and Hawksbill sea turtles during that time, most of which were under 3 kilograms body weight. As no guidelines regarding the care of oiled reptiles were available, a treatment protocol was developed.

On intake turtles were weighed, carapace measurements collected, an identification tag placed and a blood sample collected for analysis using an iSTAT®, complete blood count, chemistry panel and hydrocarbon analysis. Physical examination was performed including corneal stain with fluorescein, heart rate, respiratory rate, body temperature and oral examination. Generally turtles were moderately to heavily oiled (> 50% of body surface area), often lethargic, were mild to moderately dehydrated and sometimes bradycardic and bradypneic. A thick layer of highly viscous oil frequently coated both eyes, all oral tissues extending into the esophagus, and occluded the nares. The iSTAT® was run immediately and subcutaneous fluids supplemented with Vitamin B complex were administered at 20 ml/kg. Common electrolyte abnormalities included hypo- or hyperglycemia, hypo- or hyperkalemia, hypocalcemia, hypernatremia, and acidemia. Additives such as dextrose, potassium chloride, calcium gluconate and sodium bicarbonate were administered as needed.

Vegetable oil was applied externally to loosen the crude oil and turtles were scrubbed clean with Dawn® dishwashing detergent. Mayonnaise was applied to the eyes and periorbital tissues to loosen crude oil, and corneal ulcers were treated with topical antibiotic ointment. Oral tissues were cleaned with mayonnaise-impregnated gauze. Due to concerns over possible stress-related immunocompromise and the potential for respiratory infection, all turtles were started on prophylactic antibiotic therapy (ceftazidime 20 mg/kg intramuscularly every 3 days for 3 weeks). Turtles were also given prophylactic iron dextran (5mg/kg intramuscularly once) due to a report by Lutcavage et al. of anemia following ingestion of crude oil by juvenile loggerhead turtles.¹ Turtles were initially given activated charcoal (Toxiban®, 5ml/kg) via oral gavage; however, nearly all turtles regurgitated the charcoal despite vertical positioning post-administration. Turtles were instead gavaged a mixture of 2 parts mayonnaise to 1 part cod liver oil (5 ml/kg) which was well tolerated as an oral cathartic and cleanser. Turtles were initially placed in shallow fresh water overnight, though due to the development of hyponatremia in some cases, this was changed to salt water. A few obtunded turtles were covered with a water-based lubricant and "dry-docked" overnight. All animals were examined thoroughly the following day, including a recheck iSTAT®, administration of parenteral fluids (10 ml/kg), additional medications as needed, and another cleaning. Turtles were given a second dose of mayonnaise/cod liver oil 48 hours after intake and monitored daily until completely stable.

Acknowledgements

We are extremely grateful to the vast numbers of Audubon staff, volunteer veterinarians, technicians and biologists, too numerous to name here, who worked day and night in extreme heat and hazardous conditions to receive and care for the animals affected by this incident.

Reference

1.  Lutcavage ME, Lutz PL, Bossart GD, Hudson DM. Physiologic and clinicopathologic effects of crude oil on loggerhead sea turtles. Arch Environ Contam Toxicol 1995; 28: 417–422.