Final Report: Study of the Effects of Oil on Marine Turtles, Volume 1- Executive Summary

Florida Institute of Oceanography; Vargo, S; Lutz, P; Odell, D; Van Vleet, E; Bossart, G

The objective of this study was to determine the effects of oil on marine turtles. An experimental program was carried out on 3-20 month old loggerhead and 3-16 month old green turtles to determine behavioral and physiological effects of oil using South Louisiana Crude Oil (SLCO) preweathered for 48 hrs. The behavioral experiments indicated that both species of marine turtles had a limited ability to avoid oil slicks, but experiments to determine avoidance/attraction to floating tar balls were inconclusive. Controls (wooden balls) were struck at a greater rate than tar balls, but overall strike rates were low and interpretation complicated by feeding schedule and interspecific differences. The physiological experiments showed that the respiration, skin, some aspects of blood chemistry and composition, and salt gland function of 15-18 month old loggerhead sea turtles were significantly affected. Oil was observed clinging to the nares and eyes and in the upper; portion of the esophagus and was found in the feces of all turtles in the physiological experiments. Some similar effects were found in stranded oil fouled turtles. Based on these experimental results, it is our opinion that given the proper circumstances, sea turtles will be at risk in the event of an oil spill. Spills in the vicinity of nesting beaches are of special concern. Mitigating strategies for such an event are discussed. Dispersants with microbial nutrients are of interest, but they should only be used if they are found harmless to sea turtles.