terrapin tale: Diamonds in the Marsh

Terrapin tale finds a teller
By Rich Eldred/ reldred@…Thursday, July 6, 2006 A few years ago, Barbara Brennessel’s life was centered on microscopes, peptides, fat cells and teaching her students at Wheaton College the intricacies of microbiology, biochemistry and nutrition. Penning the definitive tome on terrapins was about as likely as editing a fan magazine for wrestling. But here it is summer 2006 and Brennessel’s 219-page “Diamonds in the Marsh” has just been published by the University of New England Press. “I actually got interested because of my daughter. Since she was a little girl, she was interested in them and as my gift to her for her birthday, I enrolled her in Bob Prescott’s field school [at Wellfleet Bay Wildlife Sanctuary] and I decided to come with her.” She had never paid much attention to turtles until then. “I’ve summered here for 25 years and I never knew about these turtles until I went to the field school,” she says. “And this is the spot to research them and check on the status of the population. This is a good training ground for my students. They are a charismatic reptile. They’re not scary like snakes. And it takes me out of my comfort zone and is a great training experience for me.” Wellfleet Bay is the northernmost home of diamondback terrapins in the United States. Usually species peter out at the end of their range, but terrapins are relatively common in Wellfleet. They are a threatened species in Massachusetts and although they have long been eaten, their habits are not that well known. Brennessel recruited Wheaton students who radio track turtles, protect nests, do genetic analysis and help with Wellfleet Bay’s capture/recapture studies. The book grew out of this field work. “No one had done it before and when I had my students, there was nothing I could give them to read to prepare for field work so I decided to put it all together and got information from scientists and other people,” Brennessel says. “Since Bob was not going to write it and Don [Lewis] was not going to write it, I did it in my spare time.” It took a couple of years and lots of travel. The turtles range all the way to Corpus Christi, Texas. “It’s actually one of the few books on one species of turtle,” Brennessel points out. “People should know about it and be aware of it, especially since it likes to live where we do in prime real estate. It is written for the general public.” “It’s a great addition to the natural history of turtles,” sanctuary director and turtle expert Bob Prescott observes. “It’s a fun easy read and it’s such a compilation of current knowledge.” Terrapins on Cape Cod Brennessel was at the sanctuary recently for a book signing and lots of terrapin talk. The turtle sports raised concentric rings on its back – the diamonds – which can be used to estimate age much like the rings of a tree. “They’re all a little different in coloring and patterning. They’re all rather unique,” Brennessel says. And they occupy a unique niche in turtledom – they don’t live in freshwater or the open ocean but only in brackish estuaries and marshes. Chesapeake Bay is really the heartland of their distribution. They are found in only one harbor in Rhode Island but live in Buzzards Bay, Pleasant Bay, at Sandy Neck in Barnstable and, in smaller numbers, in bayside marshes in Eastham, Brewster and Orleans. They carry no X or Y chromosomes so sex is determined entirely by the temperature of the nest. If the temperature is steadily above 86 degrees, the turtles are female. If it’s below 82 degrees, they are male and there’s a mix if it’s in between. As a result, in order to avoid all-male populations, the terrapins need a very sunny sandy spot, clear of shading vegetation to nest in. That brings them in contact with homeowners or vehicles. Brennessel and her students relocate nests they find in Wellfleet’s sandy roads. The new threats “The new threats are loss of habitat; that’s probably the number one factor,” she says. “The loss of salt marsh and nesting areas. Also the continued demand in Asian markets and road kill.” The old threat was the stew pot. “We’ve been finding their shells in Indian middens along with clams, oysters and other shells,” notes Brennessel. “They probably ate them in the shell by roasting the whole turtle.” Europeans held terrapins in low esteem and fed them to slaves. But tastes changed. “There was a sea change by the late 1800s,” Brennessel says. “They achieved gourmet status and they were hunted almost to the brink of extinction. The major fishery was in Chesapeake Bay.” Cape Codders used Pleasant Bay as a source for terrapins that were shipped by the barrel to Boston and New York. Terrapin stew was all the rage in all the best homes. “President [William] Taft loved terrapin stew,” Brennessel says. “He would serve it on special occasions. It was difficult to prepare so his wife paid the cook an extra $5 every time she served it.” Brennessel reprints Taft’s recipe in her book. The diced terrapin seems almost an afterthought what with four pounds of veal knuckle, fat, browned onions, carrots, tomatoes, bay leaf, marjoram, thyme and sherry. At the time, a dozen terrapins sold for more than $100. But as the supply declined so did the interest in terrapin stew, although they are still hunted in Chesapeake Bay and Brennessel is concerned about the rising demand for turtles in Asia. She’s been monitoring their reproduction in Wellfleet. “Females can store sperm for up to four years so they don’t have to mate every year [to lay eggs],” Brennessel notes. “So that leads to a question: Can a clutch of eggs be fathered by more than one turtle?” Her genetic analysis should settle that query. “Very few of the nests actually make it,” Brennessel says. “They face predation by animals [raccoons and skunks] and predation by plants – the plant roots infiltrate the plants. A number of years ago we decided to protect the nests from animals.” Her students put cages around the nests, which worked pretty well. Two years ago they head-started a nest, with help from Lewis, and they released the hatchlings with mini-radio transmitters last summer. Unlike nearly all other turtles, they didn’t sprint to the water. Instead, they secreted themselves in the marsh grass. “We find [the marsh] seems to be a nursery for the baby turtles. Moving with the tides they travel place to place but never very far. They were hiding under the Spartina [grass] in little caves they made,” she recalls. “Sometimes they went way down in the mud for long periods of time.” They also learned the young turtles ate small crustaceans, snails, insects and other shellfish and were in turn eaten by sea gulls. Details of their work and that of Lewis and Prescott in Wellfleet and Peter Auger in Barnstable are in “Diamonds in the Marsh” along with lots more. Marguerite WhildenThe Terrapin InstituteP. O. Box 51Edgewater, MD 21037Voice 410 370 9171FAX 410 757 9268www.terrapininstitute.org “It is not the strongest of the species that survive, nor the most intelligent, but the ones most responsive to change.”