The diamondback terrapin (Malaclemys terrapin) is Hilton Head Island's only truly brackish water turtle, making its home in the salt marshes and creeks of the island. It is beautiful and unusual in its coloration, with gray limbs and head spotted with black, and a top shell that has concentric dark rings on a gray or brown background; these growth rings often make the shell look carved or sculpted. Adult females are considerably larger than adult males; the top shell of a female measures 6-9 inches in length, while the male measures 4-5.5 inches in length. Young hatch from eggs laid during the months of May-July, and measure about 1-1.25 inches in length when hatched. Diamondback terrapins feed on marine worms, clams, small crabs and snails. They were hunted almost to extinction in the early part of the 1900s for their meat. Once the hunting stopped, most populations made strong comebacks. Unfortunately, they continue to face many obstacles to their survival today. As barrier islands along the east coast developed, many roads were built that passed through terrapin salt marsh habitat; when the females start to look for nesting areas in the spring, they often cross roadways and are killed by vehicles. On Hilton Head Island in the 1980s, it was common to see dozens of females trying to get across the roadways; today, it is unusual to see one. Development in or near coastal marshes continues to destroy nesting habitat, and death by drowning occurs in untended crab traps.
You can help our diamondback terrapins by checking crab traps every 1-2 hours while in the water, and storing them out of the water when not in use. You can also attach a "Bycatch Reduction Device (BRD)" to your trap to keep turtles out altogether. To learn more, go to http://www.vims.edu/research/units/projects/terrapin_brds/index.php.
SC Department of Natural Resources: www.dnr.sc.gov/cwcs/pdf/DiamondbackTerrapin.pdf