Northern diamondback terrapins are an important component of the food web. Adult terrapins primarily eat mollusks and crustaceans, including snails, fiddler crabs, and mussels. They also eat blue crabs, green crabs, marine worms, fish, and carrion.
Great Bay Terrapin Project
Conserving terrapins on southern Barnegat Bay and Great Bay through species management, education, and awareness.
Northern Diamondback Terrapins (Malaclemys terrapin terrapin) are native to New Jersey and inhabit the many miles of coastal salt marshes and estuaries along the Atlantic Coast and Delaware Bay. They live exclusively in brackish water (a mixture of both salt and fresh water). Habitat loss, mortality from being drowned in crab traps, and road mortality all pose major threats to the health of the population. Each year hundreds of terrapins are killed by motor vehicles throughout their range and here in New Jersey, Great Bay Boulevard is no exception.
Brief History of Terrapins
Terrapins were once very common and were used as a main food source of protein by Native Americans and then European settlers. In the early 1900s it was hunted so extensively that it almost faced extinction. Terrapin stew was a popular delicacy in the U.S. and terrapins were exported to several European countries. In the late 19th century, 400,000 lbs were harvested annually (True, 1887). By 1920, their population dwindled and only 823 lbs were harvested in one year on the Chesapeake Bay and cost $125/dozen. Prohibition (sherry was a main ingredient in soup) and the great depression (people could not afford high cost of terrapins) helped reduce desire and demand for terrapins. Luckily, during the 1920s, use of terrapins for food dropped in popularity. This allowed the population to slightly recover and avoid extinction. In 2002, the Northern diamondback terrapin was listed as a species of special concern in New Jersey. The listing as special concern “warrants special attention because of some evidence of decline” (NJ ENSP-Species Status Listing). Although, this status has not been offically adopted under the Endangered Species Conservation Act and terrapins are still considered to be a game species with an open season from November 1 to March 31.
Great Bay Boulevard or Seven Bridges Road is located in Little Egg Harbor, Ocean County, New Jersey. The road extends approximately 5 miles into estuarine emergent wetlands and prime Northern diamondback terrapin habitat. This road was originally constructed in the 1930s to help supply the old Crab Island Fish Factory. It was meant to connect Little Egg Harbor to Brigantine but the project was never completed. It was first paved in the 1960s and again in the 1990s.
The soft shoulders along the road provide suitable nesting sites for terrapins. The boulevard is surrounded by over 5,500 acres of protected coastal habitat (Great Bay Boulevard Wildlife Management Area – Managed by NJ Division of Fish and Wildlife), a relatively pristine, estuarine ecosystem. This road has a high a volume of traffic (mean of over 800 vehicles/day/month) in summer months when females actively search for suitable nest sites (Szerlag and McRobert 2006). Many juveniles and males also cross the road to access other small creeks and ditches that were filled from the creation of the road.
Currently from May-July there is no protection to terrapins when they cross Great Bay Blvd. from vehicle traffic. Many terrapins that cross the road are adult females who are laden with eggs and are looking for suitable nest sites. These females lay their eggs in a sand/gravel mixture where it is easy for them to dig and cover their eggs, like sandy dunes and in scrub-shrub habitat along road edges. Many female terrapins are inadvertently hit-by-car and injured or killed by motorists and people unaware of the summer nesting habits of the terrapin. Terrapins remain close to where they originated and do not make long distance migrations (Tucker, 2001). They also have very small home ranges. Therefore, over time high mortality rates from vehicle collisions may significantly reduce the local population. This creates a trend that terrapin populations cannot sustain (Avissar, 2006).
Conservation work began in 2010. Thanks to private donors we were able to purchase and install 4,000 linear feet of fence. It was installed by volunteers and employees of Exelon - Oyster Creek. Volunteers worked tirelessly to install the fence. It was a learning process for both CWF staff and volunteers since this is the first conservation project we have initiated to help protect terrapins in New Jersey. Driving in stakes was tough in the highly compacted soils along the road. Careful attention was paid to any gaps that were in the fence. Landscaping ground staples were installed to help hold the fence tight to the ground.
In June and July the fence was maintained and repaired after several repeated attempts by people to damage it. Sections of the fence drooped in the heat of the day. The fence was up until early September, well after terrapins were finished nesting. The fence was vandelized in several sections and was easier to remove then keep up. We determined that other methods were needed for a more permanent installation.
With the funding that we received in 2010, a brochure was developed and printed. It is now available at local marinas in area, the Jacques Cousteau National Research Reserve Education Center and the Tuckerton Seaport. The brochure has information about terrapins and their threats, our plan and ways to help terrapins. We also installed three "Terrapin X-ING" signs along the road. To date, only one sign remains after several have been stolen. In the future we plan to keep one sign up year-round and install more during the actual nesting season to raise awareness.
Additional work in 2011
In 2011, the fence was re-installed (permanantly) in early June with help from many volunteers and in-kind support from Sambol Construction and the Township of Little Egg Harbor. NJN News was present and documented our work along the road. In place of the wood posts, metal ones created a much more stable way to hold the fence up.
In the spring we recruited several volunteers to act as "terrapin stewards." The volunteers periodically checked fencing and crossing areas for terrapins. They conducted road patrols and recorded sightings of live and dead individuals. The data collected is submitted to the Endangered and Nongame Species Program for inclusion into the Landscape Project. The stewards also educated the public about the importance of terrapins and their threats in the environment.
We inquired about the speed on the road since there were no posted speed limits and found that it was 50mph. This was unacceptable for a road that bisects the largest WMA on the coast of NJ. We attended several environmental comission meetings and a town council meeting to stress our concerns. The township said they were going to conduct a study of road traffic but never did.
Current work this year
This winter we created an online petition to ask for the township to reduce the speed on the road. Check out the petition here.
This past spring we installed 1,000 linear feet of a new type of barrier with financial support from US Fish & Wildife. The new barrier is a rigid corrugated plastic tubing that is cut in half and installed in a trench, then backfilled. We believe this new type of barrier will outperform any other type of barrier used in the field. It will not require maintenance after being installed. It is low and not intrusive to the eye. The only maintenance that will be needed is the control of vegetation along its length (this is currently needed with all other types of barriers). We're also happy to be supporting workers and companies in New Jersey. This pipe is manufactured by ADS or Advanced Drainage Systems, Inc. in Logan Township.
This past summer we had an intern work with us to help us monitor the local population and reduce road kills. She collected data on terrapins encountered on the road to compare to previous studies. We also had several volunteers who acted as "Terrapin Stewards" who patrolled the road and recorded sightings, and helped to make sure the many terrapins that entered the roadway made it safely across. We're summarizing data that will be relased later this year. We do know that the total number of road kills is below the average recorded before our conservation project began in 2010.
Adult females are smaller and less numerous now, and the selective mortality of these adult females “is a trend that terrapin populations cannot sustain” (Avissar 2006).
HOW YOU CAN HELP
This project is completely funded by donations and all of it goes to help terrapins! If you would like to help fund this project to prevent terrapins from being hit-by-car, please support our cause by making a donation today!
Help spread the word for people to "Be Terrapin Aware" while driving along roads in the coastal region of New Jersey. Help install or maintain our 4,000 foot barrier fence along Great Bay Blvd. Contact Ben if you are interested in helping out!
Schedule an educational "Great Bay Terrapin Project" presentation, which covers Northern diamondback terrapin identification, habitat, life history, human impacts, and the challenges of helping to protect terrapins in the coastal zone of New Jersey. This is a great program for schools, civic organizations and scouting groups.
The Sandpaper letter to the editor - March 14, 2012 - 756.2KB
The Sandpaper article by Pat Johnson - March 14, 2012 Page22 - 348.0KB
1. Cape Horn Marina Inc.
570 Great Bay Blvd.
Little Egg Harbor, NJ 08087
630 Great Bay Boulevard
Tuckerton, NJ 08087
3. Ocean County Vocational Technical School
MATES Program – Project Terrapin
Bureau of Land Management
Central Region Superintendent: Ray Porutski
5. Little Egg Harbor Environmental Commission and Public Works
Little Egg Harbor, NJ
- Avissar, Naomi G. 2006. Changes in Population Structure of Diamondback Terrapins (Malaclemys terrapin terrapin) in a Previously Surveyed Creek in Southern New Jersey. Chelonian Conservation and Biology, Volume 5, Number 1. 154-159
- Hoden, R., Able K.W. 2003. Habitat use and road mortality of Diamondback terrapins (Malaclemys terrapin) in the Jacques Cousteau National Estuarine Research Reserve at Mullica River – Great Bay in southern New Jersey. Jacques Cousteau NERR Technical Report 100–24.
- Szerlag, S., and S. P. McRobert. 2006. Road occurrence and mortality of the northern diamondback terrapin. Applied Herpetology 3:27-37.
- True, F. W. 1887. The turtle and terrapin fisheries, pp. 493–503. In: G.B. Goode et al. (eds.), The Fisheries and Fishery Industries of the United States. Section 5, volume 2, part XIX. U.S. Commission on Fisheries, Government Printing Office, Washington, D.C.
- Tucker, A. D., J. W. Gibbons, and J. L. Greene. 2001. Estimates of adult survival and migration for diamondback terrapins: conservation insight from local extirpation within a metapopulation. Canadian Journal of Zoology 79:2199-2209
Future Goals for the Terrapin Project:
- Obtain funding through a grant from a private foundation or corporation
- Record terrapin sightings to more accurately map range in New Jersey
- Record live and dead individuals when encountered on roads to help identify road kill "hot spots"
- Provide data to state, county, and local government to help influence road improvement projects that intersect with terrapin habitat to reduce road kills
- Test additional types of barriers that require less maintenance
CWF Staff Published Literature:
Szerlag-Egger and McRobert 2007 - 1.7MB
Szerlag and McRobert 2006 - 323.8KB
2011 Great Bay Terrapin Project - 111.6KB
Terrapin Brochure - 751.1KB
Ben Wurst, Habitat Program Manager: Email
Stephanie Egger, Wildlife Biologist: Email
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