Mordecai Island’s cove is home to a small population of Northern Diamondback Terrapins (Malaclemys terrapin terrapin), a New Jersey protected brackish water species that is indigenous to coastal marsh regions. The island’s safe and diverse habitats attract terrapins to bask, feed and nest. Nesting occurs from late May through July on sandy, sunny, non-vegetated areas that are above the high tide line. However, erosion, rising sea levels and urban development have created fewer suitable nesting habitats for successful egg incubation. Terrapins are now navigating over bulkheads, crossing busy streets and nesting further from the marsh in less desirable substrates, which has impacted the population’s survival. 

In 2016, a Terrapin Garden was established on an elevated sand mound at the southwest corner of Mordecai island. In partnership with Project Terrapin and Terrapin Nesting Project, eggs from at-risk nests within Holgate, NJ were relocated to this site and allowed to incubate. The conservation goal of this project was to create a habitat for natural and artificial nesting, establish site fidelity, and repopulation of the species.