The Western Pond Turtle (Actinemys marmorata) is the only common freshwater turtle native to California and occurs in a diverse array of habitats from Western Washington State to Northern Baja California. Many populations of this species have been lost or severely reduced in numbers due to habitat loss, climate change, and competition with invasive species. The Western Pond Turtle has been listed as a species of special concern by the state of California, and is listed as an endangered species in Washington and Oregon.
Captive breeding is a critical management strategy in the recovery and reintroduction of threatened and endangered species. However, if breeding is allowed between very distantly related individuals of the same species or members of two different subspecies, this may lead to a decline in individual or population fitness. In this study, we are collaborating with several zoos in California to help reduce the risk of inbreeding depression and outbreeding depression in captive Western Pond Turtle populations. At CSU Fresno, we are using DNA sequencing to identify the subspecies and genetic origin of captive Western Pond Turtles at the zoos we are collaborating with to help guide captive breeding protocols and reintroduction plans.
Results/Conclusions
Two distinct populations of Western Pond Turtles have been identified in the northern and southern regions of this species’ native habitat. Diagnostic genetic markers have been established within the mitochondrial DNA of Western Pond Turtles to identify individuals with divergent ND4 haplotypes. We have used this marker to identify subspecies status for twenty two captive individuals with twelve northern (Actinemys m. marmorata) and ten southern (Actinemys m. pallida) individuals. Once northern and southern males and females have been identified, breeding will be restricted to individuals of the same subspecies. Our goal is to expand this project to include all captive rearing facilities throughout California, Oregon, and Washington. This project will contribute to the conservation and restoration of this species, and will help further our ability to protect others in the future. One limitation of this study is that captive individuals of hybrid ancestry are impossible to identify using only mtDNA markers. Future research will include multiple nuclear loci.