Typically, we go out in small motor boats in the morning to check or set turtle traps. We bring the captured terrapins back to our laboratory which we affectionately refer to as the Marine Station. In the Marine Station, we "process" the terrapins with the help of our Earthwatch volunteers. Basically, this means that we measure (mass and various shell lengths) and mark each individual terrapin with unique codes that allow us to recognize that specific terrapin in case we catch it again in the future. We also check each terrapin for the presence of new or healed injuries. We've been keeping a record of the presence and location of each injury for each individual terrapin since 2006. The most common injuries include missing limbs and shell damage to the carapace (top shell) or plastron (bottom shell). We also frequently capture terrapins with boat propeller injuries. These types of injuries are easy to identify due to the major damage to the carapace and plastron, and most times you can actually see a telltale slash mark through the terrapin.
The figure at the top of this post shows the frequency of major terrapin injury in the northern and the southern parts of the Edwin B. Forsythe Wildlife Refuge over the past six years. Only major injuries are included here, and major injuries were considered to be missing limbs or major damage to the shell, head, or tail. When the Earthwatch project started in 2006, only 13% of the terrapins we captured had major injuries. However, we found that 23 to 24% of the terrapins captured this past summer had major injuries.
Terrapins can obtain injuries from natural and anthropogenic sources. Missing limbs are oftentimes attributed to land predators such as raccoons. Major shell damage tends to be due to anthropogenic (human-generated) impacts such as boat propellers or automobiles. There's not too much that we can do about natural causes of injuries; however, there are some steps we could take to decrease human-caused injuries. Partial or complete closures of some wildlife areas to boating may be necessary to protect terrapins from boat strike injuries. Boating speed limits could also be helpful, especially in sensitive areas such as near nesting beaches. In order to lessen the impact of human-generated injuries on the terrapin population in Barnegat Bay, we need to keep collecting data on terrapins and injury rates. If you want to help save the terrapins, please consider signing up for one of our Earthwatch expeditions. Earthwatch volunteers truly are indispensable members of our research team on the conservation of diamondback terrapins in Barnegat Bay, New Jersey.
