Human Consumption Safety of Snapping Turtles and Diamondback Terrapins

The common snapping turtles (Chelydra serpentina serpentina) and diamondback terrapins (Malaclemys terrapin) are legally harvested throughout the State of New Jersey. Turtles are usually sold for human consumption at both local and global markets.  Since turtles are long-lived omnivores, they can bioaccumulate high concentrations of pollutants in their tissues, such as mercury.  Mercury is of special concern because it is the one metal that biomagnifies (due to the common organic form, methylmercury, or MeHg, found in aquatic environments, having a predilection for lipidrich tissues). High levels of mercury have been reported in turtle eggs, fat, organs, blood, shell, and muscle.  This study aims to identify a quick and benign method to measure mercury contents in turtle muscles in order to assess human consumption safety of snapping turtles and diamondback terrapins.  We plan to analyze mercury concentrations carapace, blood and front leg muscle of both turtle species collected from the Cape May area and the NJ Meadowlands.  

The common snapping turtles are long-lived organisms with a delayed sexual maturity and high egg and juvenile mortalities; thus, harvesting wild snapping turtles might be unsustainable. Another component of this project is to assess the sustainability of the common snapping turtle populations in NJ.  Currently, the State of New Jersey has limited regulation toward snapping turtle harvesting.  Snapping turtles can be legally harvested commercially from March through October and recreationally throughout the year with the exception of nesting season (May 1st to June 15th).  “Any person with a valid fishing license or those entitled to fish without a license” may take up to three snapping turtles a day either by traps or with hands, either in water or on land, either adults or juvenile, with no reporting requirement (NJDEP). In recent years, increases have been documented in numbers of snapping turtles harvested and commercial harvesting permit holders in NJ.  This research project will estimate the current snapping turtle population size at selected waterbodies and assess sustainability of the populations.  We will also examine the economic impacts of eliminating the current snapping turtle harvesting program in NJ.