Diamondback Terrapin Research

Kiawah Island, South Carolina


For the past eight years, Davidson College students under the guidance of Mike Dorcas have collaborated with the University of Georgia's Savannah River Ecology Laboratory in long-term research on Kiawah Island's diamondback terrapins (Malaclemys terrapin). Initiated by Whit Gibbons, in 1983, this mark-recapture study monitors the M. terrapin population of the tidal creek tributaries of the Kiawah River. Diamondback terrapins are the only turtle that inhabits estuarine habitats in the United States and were commercially harvested until recently. They are still commercially harvested in some states (e.g., Maryland). Terrapin populations have been experiencing declines throughout their range due to several threats discussed below. Visit the Diamondback Terrapin Working Group website for more info on research and conservation efforts throughout their range.

This long-term study consists of intensively sampling tidal creeks at low tide. We use seines and trammel nets to capture terrapins, which we bring to shore to mark and measure before release. From these data, we can evaluate changes in sex ratios, size, and age and monitor movements and injuries of terrapins. Over these 23 years, more than 1400 individual diamondback terrapins have been captured and many of these have been recaptured. One terrapin has been captured 14 times.

Using these long-term data, we have documented population declines and been able to hypothesize about potential causes of declines surrounding Kiawah Island. Various threats throughout their range include crab pot mortality, road mortality, motorized watercraft, and effects of habitat alteration. Recent studies (Dorcas et al. 2007) have shown that in the Kiawah Island population, crab trapping has created a larger, female-biased population, which indicates that males and younger terrapins are affected by this threat. Because terrapins are declining throughout their range, and long term research is essential to understanding and protecting these estuarine turtles. Thus, the Davidson College Herpetology Laboratory and Savannah River Ecology Laboratory plan to continue their research on diamondback terrapins at Kiawah Island.


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This website created by Leigh Anne Harden and Kristen Cecala.
Some photos taken by J.D. Willson, Tom Luhring, and Cris Hagen.

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Questions? Contact Michael Dorcas