Blood profiles for the Western Pond Turtle (Emys marmorata) from two Northern California habitats: Baselines from a nature reserve and comparison to a population at a wastewater treatment facility

Background/Question/Methods

Freshwater turtles worldwide are declining due to a variety of human caused impacts.  The Western Pond Turtle (Emys marmorata) is native to the pacific coastal states of the United States and is also in decline. Many Western Pond Turtles live in human-modified habitats and it is likely that these changes to their environment influence their health.  Critical information is lacking on the baseline ranges for simple blood profiles in healthy individuals in this species and the impacts of habitat change to basic physiology in this species is largely unknown.  In 2011 and 2012, we captured Western Pond Turtles from two habitats in Northern California, a pristine nature reserve, and a wastewater treatment facility’s oxidation ponds. Turtles were examined for external signs of disease and had blood tests performed, which are commonly used by veterinarians in evaluating health.  The blood tests that were performed included determination of hematocrit and thirteen serum chemistries. 

Results/Conclusions

We present baseline blood profiles for a healthy, free-ranging Western Pond Turtle population living on a nature reserve (n=61), and we also compared blood profiles between a sample of male turtles from the nature reserve (n=28) and the wastewater facility (n=26) populations.  We found significant differences in eight blood chemistries between healthy male and female turtles from the nature reserve, highlighting the importance of evaluating blood profiles in each sex separately.  We also found significant differences in ten blood analytes between male turtles from the nature reserve and wastewater treatment facility, suggesting differences in physiology between the populations.  The blood profile baselines from the nature reserve population will be helpful to wildlife veterinarians in evaluating disease in this species and possibly other Emydid turtles.  Furthermore, the differences in blood profiles between populations underscores that animals from different locations can have different physiologies and that blood profiles, with further study, may be useful in assessing habitat suitability.  We hope that managers may use this work in assessing the health of Western Pond turtle populations and plan conservation strategies in altered landscapes.