Diamondback in the Rough

Terrapin populations are on firmer ground, but there is still work to be done.

Published November 04, 2014

In a muddy coastal marsh off the Atlantic, shoreline grasses wave gently in the warm summer breeze. A small turtle pops its white, distinctly patterned head above the water for a gulp of air before diving swiftly back beneath the surface.

Diamondback terrapins live along the Atlantic and Gulf coasts, from Cape Cod to Corpus Christi. With seven recognized subspecies, they are largely distinguished by the diamond pattern on their shells.

Each varying in color and pattern, no two terrapins look exactly alike. Large, webbed feet make these reptiles adept swimmers, a necessary skill for enduring the strong currents and tidal flows of their habitat.

In colder parts of their range, diamondback terrapins burrow in the bottom mud to hibernate through the frigid winter. By dramatically slowing their metabolism and absorbing dissolved oxygen from the water through their mouth linking and tail openings, they can survive completely submerged for months. The terrapins emerge from hibernation in the early spring just in time to mate.

Commercial Commodity

Demand for terrapin stew in the late 19th and early 20th centuries resulted in dramatic population declines. A major commercial fishery developed in the mid-Atlantic to satisfy the growing market, making terrapins one of the most economically valuable reptile species in the world.

Adult terrapins were being removed from the wild faster than they could reproduce, reducing the populations to dangerously low levels. This unsustainable practice made terrapins increasingly rare. Prices skyrocketed to the point that their harvest was no longer profitable.

Fun Fact: Some speculate that the removal of sherry, a key ingredient in terrapin stew, from the market during Prohibition also played a part in the popular stew falling out of favor.

The decline in demand provided a much needed respite for wild terrapin populations to begin to recover. However, in recent years, Asian buyers connected with U.S. seafood suppliers have fueled another unsustainable terrapin commercial fishery overseas.

In response, the National Aquarium and others successfully lobbied for the complete closure of Maryland’s terrapin trade in the early 2000s.

Thoughtful Fishing

Today, terrapins face different challenges.

Primarily used by commercial crabbers, crab pots are efficient for catching blue crabs. Soon after the rise of the commercial crab trap, the state passed a law prohibiting their use in the Bay’s tributaries, but an exception was later given to waterfront property owners.

These recreational crabbers are allowed to cast two pots from their private piers—the very creeks and tidal marshes terrapins inhabit. To prevent the drowning of terrapins and other turtles unintentionally caught in the traps, the state of Maryland now requires crab pot entrances to be outfitted with a by catch reduction ring, also known as a turtle excluder device (TED). This simple device allows crabs to enter the trap while keeping air-breathing terrapins out.

Down the Line

Reinforcing turtle-safe crabbing practices is just one step toward protecting terrapins. Preserving estuaries and beaches where these turtles live and nest is also critical.

Tidal marshes are teeming with life, home to not only the diamondback terrapins, but to countless other species as well, including blue crabs, muskrats, otters, ducks and a variety of fish. They serve as a buffer between Bay waters and lad, dissipating wave energy, slowing total waters and preventing shoreline erosion during high tides and storms.

Known colloquially as nature’s nurseries, estuaries also provide safe shelter for many animal moms to raise their young. Eggs tuck in tall grasses or nestled in the mud beneath the murky water are less susceptible to predators. Abundant plant life proves a bounty of food and shelter, making tidal marshes ideal spot overs for migrating birds as they travel the Atlantic flyway.