Hauswaldt, J.S.*; Glenn, T.C.: Population genetic structure of the Diamondback terrapin, Malaclemys terrapin centrata, using microsatellite DNA markers

The Diamondback terrapin is the only species of turtle in North America that exclusively inhabits brackish waters. Seven subspecies occur in separate regions from Cape Cod to western Texas. At the beginning of last century terrapin numbers were drastically reduced because of exploitation for the soup trade. Since commercial harvest became unprofitable in the 1920s, most populations have recovered. However, terrapins face new human threats: habitat destruction and fragmentation, pollution, motor boating, and traffic that kills nesting females. Incidental killing by crab trapping is considered to be one of the major threats. Currently little is known about the population genetic structure and mating biology. According to mark-recapture data, terrapins have high site fidelity, staying in the same tidal creeks for many years. We are initiating studies to assess the effective population size, breeding structure, and impacts of human activities for terrapin populations from coastal South Carolina and Georgia using microsatellite DNA markers. Results on the isolation of microsatellite markers and preliminary data on the genetic population structure will be presented.