| A large crude oil spill in the John Heinz National Wildlife Refuge impacted the reproduction of resident turtle populations. The goal of this group of studies was to determine the effect of crude oil exposure on female snapping turtle (Chelydra serpentina) and painted turtle (Chrysemys picta) fertility, reproductive output, and development of offspring. There was no significant difference in egg fertility between female snapping turtles exposed to oil or control turtles. However, female snapping turtles had significantly lower fertility of eggs in 2002 compared to 2000. There was no difference in reproductive output as measured by relative clutch mass (RCM) between exposure groups or years for snapping turtles or painted turtles. Embryonic death was greater and hatching success lower for snapping turtle clutches from oil exposed females compared to controls in 2000 but not 2002. Most snapping turtle embryos died early in development, and there were significantly more early deaths for oil exposed Chelydra than controls. Chrysemys had a greater incidence of embryonic deaths than Chelydra. Control painted turtles not only had a higher incidence of abnormality than control snapping turtles, but malformations were more severe in the former than the latter. Lethal deformities were dominant in both snapping turtle and painted turtle control embryos in 2000 but not 2002. Tail and shell abnormalities were most common in snapping turtles both years, while dwarfism and shell abnormalities were most common for painted turtles. Oil exposure exacerbated developmental problems in snapping turtles, causing increased incidence and severity of deformity in embryos. Both species exhibit high rates of embryonic and adult deformity in the refuge. Although the refuge offers many advantages to the resident turtle populations, background pollution places a developmental burden on the life history of these turtles that was exacerbated by exposure to crude oil. |
