Survival and behavior of freshwater turtles after rehabilitation from an oil spill

Abstract

An oil spill in February 2000 at the John Heinz National Wildlife Refuge in southeastern Pennsylvania affected four species of freshwater turtles including painted turtles (Chrysemys picta), snapping turtles (Chelydra serpentina), red-eared slider turtles (Trachemys scripta), and red-bellied turtles (Pseudemys rubriventris). In the summer and fall of 2000, there were no differences in survival, home range, and temperature preference of 16 oil exposed/rehabilitated (OER) turtles, 18 possibly exposed (PE) turtles, and 32 non-exposed (NE) turtles as measured with temperature sensitive radio transmitters. Post-release mortality or transmitter loss was not correlated to oil exposure (OER=25%, PE=22%, NE=31%). There were no statistically significant differences in home range minimum convex polygon area, (0.28<P <0.87) and water temperature preference (0.35<P <0.99) between OER, PE, and NE male and female C. picta, C. serpentina, and T. scripta. Mean home ranges scaled from 5.0 ha ±4.1 (male C. serpentina ) to 25.5 ha ±5.0 (male P. rubriventris) and mean water temperatures occupied varied from 19.6 °C±6.9 (female C. serpentina) to 22.3 °C±8.5 (female C. picta). Rehabilitation of oil exposed freshwater turtles is effective in restoring these animals to normal behavior in nature.