Intake and Treatment of Oiled Sea Turtles in Louisiana during the 2010 BP Deepwater Horizon Oil Spill
Cara L. Field, DVM, PhD; Michele L. Kelley, BS; Robert A. MacLean, DVM
On April 20, 2010, the offshore oil rig Deepwater Horizon exploded off the Louisiana coast, resulting in the spillage of millions of barrels 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 sea turtles, including Kemp’s ridley (Lepidochelys kempii), greens (Chelonia mydas), loggerheads (Caretta caretta), and hawksbills (Eretmochelys imbricata), 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, measured, and identified with a tag. A blood sample was collected from the dorsal cervical sinus for immediate analysis using an i-STAT® CG8 (Abbott Point of Care, Inc., Princeton, NJ, 08540 USA) and submitted for a complete blood count, chemistry panel, and hydrocarbon analysis. Physical examination was performed including corneal stain with fluorescein, heart rate by doppler, respiratory rate, body temperature, and oral examination. Generally, turtles were moderately to heavily oiled, often lethargic, were mild to moderately dehydrated, and some were bradycardic and bradypneic. A thick layer of highly viscous oil frequently occluded the nares and coated both eyes and all oral tissues extending into the esophagus. Equal volumes of 0.9% saline and lactated Ringer’s solution supplemented with vitamin B complex (0.1 to 0.2 ml/kg) were administered SC at 20 ml/kg. Common blood abnormalities from the i-STAT included hypo- or hyperglycemia, hypo- or hyperkalemia, hypocalcemia, hypernatremia, and acidemia. Additives such as dextrose, potassium chloride, calcium gluconate, and sodium bicarbonate were administered when medically appropriate.
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 compromise from crude oil exposure or aspiration, all turtles were started on prophylactic antibiotic therapy (ceftazidime, Fortaz, GlaxoSmithKline, Research Triangle Park, North Carolina 27709 USA, 20 mg/kg IM every three days for three weeks). Turtles were also given prophylactic iron dextran (5 mg/kg IM once) due to a report of anemia following ingestion of crude oil by juvenile loggerhead turtles.1 Turtles were initially given activated charcoal (Toxiban®, Lloyd Inc., Shenandoah, Iowa 51601 USA, 5 ml/kg) via oral gavage; however, nearly all turtles regurgitated the charcoal despite vertical positioning post-administration. Turtles were instead gavaged a mixture of two parts mayonnaise to one part cod liver oil (5 ml/kg) which was well-tolerated as an oral cathartic and emulsifier. Turtles were initially placed in shallow fresh water for four days, though due to the development of severe hyponatremia in some cases, this was changed to 25 ppt 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 i-STAT®, 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.
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.
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.