Effects of Geographic Origin and Incubation Temperature
on Hatchling Snapping Turtles, Chelydra serpentina:
Implications for Turtle Conservation Practices
across the Species’ Range


Department of Zoology, University of Guelph, Guelph, Ontario N1G 2W1, Canada

        ABSTRACT:  Snapping turtle eggs from four distinct populations across the species’ North American range were artificially incubated at constant temperatures bordering the two pivotal, sex-determining temperatures.  The hatchlings were then reared under constant laboratory conditions to investigate differences in survival in relation to incubation temperatures, geographic origin, and food availability.  Both embryo and hatchling mortality were higher in eggs incubated under colder temperatures, particularly in the northernmost population.  Embryo mortality was high in eggs from the two southern populations, but hatchlings from those populations had significantly lower mortality than hatchlings from the two northern populations.  Variation in embryo viability and hatchling survival between populations indicates that each population responds differently to similar conditions in captivity, and each population should be considered unique with respect to criteria affecting population and individual survival and growth.
        Our findings and those of others indicate that captive rearing of hatchlings of freshwater turtles may produce animals with poor rates of survival.  The financial costs associated with this practice, the minimal potential for population recovery as evidenced by life table analysis, and many years of unsuccessful release experiments indicate that captive rearing and headstarting practices should be reconsidered in favor of other, more effective conservation programs.

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