This site is in development, and your current browser is v. 2

Diamondback Terrapin Surveys

Annual Diamondback Terrapin Surveys

2021 Survey Results

The Maryland Coastal Bays Program has been collecting a variety of data relating to diamondback terrapin populations in the Coastal Bays. Organized terrapin headcount surveys began in 2012 in collaboration with Maryland DNR and other members of the diamondback terrapin work group.

The current population status of this terrapin in the Coastal Bays is poorly understood.  To better understand its status, MCBP continues to coordinate these counts annually, engaging the community on protecting Maryland’s state reptile.

The surveys take place in the Coastal Bays, including brackish-water creeks, throughout a designated week. The week is typically the end of May, which is their their courtship season.

Counts take place both on water and on land. From motorboats to kayaks and SUPs, all are encouraged to participate. MCBP conducts several trainings prior to the count. Terrapins are the only turtle occupying brackish water, but other turtles, such as snapping turtles, may venture into more brackish water, so it’s important that you are trained to identify the correct species.

Locations of surveys depend on the number of crews that are available and may take place in all of Maryland’s Coastal Bays. If you are interested in participating in the survey, please contact Katherine Phillips at

The diamondback terrapin is Maryland’s state reptile. Inhabiting the brackish waters in the bays and creeks of the Atlantic and Gulf coasts, it is the only turtle in North America restricted to estuaries. Relatively little is known about this species; terrapin have been threatened historically and its numbers continue to decline in some parts of its range.

Numerous conservation organizations, research scientists, and private individuals are researching terrapins and working to help protect this beautiful natural resource. Terrapin are considered a keystone species because they provide high quality food for many species higher in the food web, and they control numbers of periwinkle snails and invasive pests. The loss of an integral species like terrapin could have drastic ripple effects on ecosystems.

According to research from the Virginia Institute of Marine Science, diamondback terrapin face numerous threats, many of which are human related. Habitat loss, climate change, boat strikes, and nest predation by household animals and generalist species, like raccoons and gulls, have all contributed to the stress put on the terrapin population.

A serious problem that you can do something about is crab pot entrapment. Terrapin enter crab pots the same way crabs do, attracted by the same bait, and are then consequently trapped. Turtles have lungs not gills, so if someone is not checking a crab pot regularly, the terrapin can drown. Recreational pots are the most dangerous because they are typically set in shallow water where smaller terrapin, capable of getting caught, spend more time. Installation of a bycatch reduction device will stop most terrapin from entering a crab pot, but still allow the biggest crabs through.

Waterfront property owners are legally allowed to crab with a maximum of two recreational crab pots. Maryland regulation requires each entrance be equipped with a by-catch reduction device (BRD).

Brochure on Turtle Excluder

Turtle Excluder PSA

Contribute Online

Become a member of the Coastal Bays Foundation and donate online securely through PayPal. Your financial contribution will go toward protecting our watershed, its habitat, and wildlife. The Maryland Coastal Bays Program Foundation is a 501(c)(3) nonprofit; all donations are tax deductible.