Second Workshop on the Ecology,
Status, and Conservation of Diamondback Terrapins

The Wetlands Institute, Stone Harbor, New Jersey
October 6–8, 2000

Workshop Logo


Ehret, Dana and Kelly Hayes.  2000.  Terrapins and tires: Coastal carnage at the Jersey Shore
Gauthier, D. et al.  2000.  Terrapin Research in Southern New England.
Jenkins, C. David Jr., Paul G. Scarlett, and J. Richard Trout.  2000.  Effect of two designs of terrapin excluder devices on the catch of blue crabs in commercial-style crab pots.
Nelson, David H., John J. Dindo, and Roger C. Wood.  2000.  Preliminary status of diamondback terrapins in the vicinity of Mobile Bay, Alabama.
Smith, Kevin and Marguerite Whilden.  2000.  Diamondback terrapin conservation and habitat management in Maryland.

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The Status of Diamondback Terrapins
in Bayville Marsh, Long Island, New York

Marc Bossert

C.W. Post campus of Long Island University, New York

This year we initiated a study of terrapins in Bayville Marsh, a shallow embayment of the Long Island Sound, just west of Center Island, New York. Terrapins are found in two distinct concentrations (apparently with little movement between the two), separated by just over 3km. Turtles in both of these primary areas have been studied in the past, in 1969 (mainly the eastern side) and in 1991 (mainly the western side). Both previous studies indicated large breeding populations but also warned of evidence of sparse recruitment. Our goal was to reexamine the terrapins in these areas and compare our findings with the past studies.

Here we report the results of a capture-recapture study of the eastern population, including estimated population size, sex ratio, and size frequencies. We also report on a preliminary reconnaissance and classification of nesting habitat, nesting behavior, and hatchling success. We will discuss the behavior of hatchlings in Bayville Marsh and enumerate the main perceived threats to the long-term health of these populations.

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The Status of Malaclemys terrapin macrospilota
at Tarpon Key, Tampa Bay, Florida

C. Scott Boykin

Eckerd College, St. Petersburg, Florida

Three sampling methods were utilized to capture M.t. macrospilota during the months of August through January of ’98 and ’99. This report will yield data taken from 120 marked individuals, 78 recaptures and 29 predated adults. Data will be presented in the following areas: size classes, sex ratio, CPUF, fecal samples, adult mortality, habitat use and movement, barnacle loads, morphological variations and pit tag retention. Current data indicates that the population is female biased with tremendous morphological variation and that raccoons are responsible for a significant reduction of the closed population through nest predation and adult mortality.

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Terrapin Research at Gateway National Recreational Area

Russell Burke

Department of Biology, Hofstra University, Hempstead, New York

A long-term research program investigating the ecology and conservation of diamondback terrapins was begun at Gateway National Recreational Area in 1998. So far this work has focused the Jamaica Bay Wildlife Refuge Unit of GRNA. Over 2000 nests/year are laid at JBWR, and nest mortality has risen by 90% since raccoons were introduced onto the main island of JBWR. Raccoons are also now preying on adult terrapins. It is unclear whether this has had an impact on terrapin populations, in part because we are just beginning to examine nesting and predation on the numerous smaller islands in Jamaica Bay. We are attempting to estimate the size of the terrapin population so we can detect trends. We are also beginning a movement study using sonic transmitters, along with a tag-reward system, that we hope will reveal short term and long term movement. Finally, we have begun a study of raccoon behavior that we hope will lead to management options to reduce their predation on terrapins.

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Studying Terrapins in Northeastern Florida

Joseph A. Butler

Department of Natural Sciences, University of North Florida, Jacksonville, FL

I have studied diamondback terrapins (Malaclemys terrapin centra) in Duval and Nassau Counties of northeastern Florida since 1995. Part of my charge was to test various capture methods. I found that otter-trawling, gill netting, and cast netting was effective. I also trapped successfully for two seasons with crab pots modified (after Roosenburg’s model) so that the captive terrapins did not drown.

My colleagues and I also discovered an important nesting beach during the first study year. Since then we have monitored numerous aspects of nesting biology. We determined mean clutch size to be 6.7 using a combination of X-rayed females and excavated nests. Nesting occurs from early May through mid to late July, and hatching begins early July and continues through September. In early seasons 33% of marked nests were depredated, mostly by raccoons. Another 24% were washed away by high tides. That year 23% of marked nests hatched.

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Effect of Four Bycatch Reduction Devices
on Diamondback Terrapin (Malaclemys terrapin) Capture and
Blue Crab (Callinectes sapidus) Harvest in the Delaware Estuary

Randall V. Cole1 and Thomas E. Helser1, 2

1Delaware Division of Fish and Wildlife, Little Creek, DE
2National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Seattle WA

Diamondback terrapins, Malaclemys terrapin, face declining populations throughout their expansive range from bycatch mortality in commercial and recreational crab pots. Conservation efforts in recent years have focused on the use of bycatch reduction devices (BRDs) installed in commercial style crab pots, but no standard configuration of BRD is presently in use. We conducted a four-year study between 1997 and 2000 to investigate the impact of four BRDs on diamondback terrapin capture and its effect on blue crab, Callinectes sapidus, catch and average size. A total of 52 sets consisting of five replicate blue crab pots for each BRD treatment and controls was deployed at random in 10 tidal tributaries and inland bays within the Delaware Estuary. The BRD sizes tested were: 5.0 x 10.0, 5.0 x 12.0, 4.5 x 12.0, and 3.8 x 12.0 cm. In 1997–1998 when we tested the 5.0 x 10cm BRD, a total of 137 diamondback terrapins and 996 legal sized blue crabs (³ 127 nm) were caught. We observed a statistically significant reduction (p < 0.01) reduction in terrapin catches (59%) in pots fitted with 5 x 10 BRD vs. controls, with no statistical differences in blue crab catches. In 1999–2000, we captured a total of 235 terrapins and 2526 legal sized blue crabs. The 5.0 x 12.0 cm BRD did not show a statistically significant reduction in overall terrapin catches (-12%) nor was there a significant loss of legal sized blue crab catches. Only a nominal loss (12%) of legal sized blue crab catches was first observed in pots fitted with the 4.5 x 12.0 cm BRDs, while we observed a significant (p < 0.01) reduction in diamondback terrapin captures (38% male and 96% female). No terrapins were captured in the smallest BRD (3.8 x 12.0 cm), however, losses of legal sized blue crab catches were substantial (26%). We therefore recommend the use of 4.5 x 12.0 cm BRD for use in recreational crab posts as a conservation measure as this would effectively protect all sub-adult and reproductive females with a minimal loss of legal blue crabs. We also stress the importance of the use of BRDs in concert with other conservation measures such as the preservation of nesting beaches.

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Terrapins and Traps: Testing the Impact
of Excluders upon Both Crabs and Turtles

Jean Doherty1, 2 and Jennifer Wood1, 3

1The Wetlands Institute, Stone Harbor, NJ
2Undergraduate Student at Rowan University, Glassboro, NJ
3Undergraduate Student at Richard Stockton College of New Jersey, Pomona, NJ

Terrapin excluders were invented and first tested at the Wetlands Institute in the early 1990s. In recent years we have been focusing on the experiments related to political repercussions arising from the implementation of New Jersey’s first pioneering excluder regulation in 1998. We have repeatedly demonstrated that excluders substantially reduce the number of terrapins caught in commercial crab traps. In particular, excluders will prevent all adult females from entering traps. Large-scale experiments (e.g., nearly 18,000 blue crabs were caught and measured in 1998) have also shown that (1) excluders do not reduce the number of marketable-sized crabs caught, (2) traps with excluders will often catch increased numbers of marketable-sized crabs compared to traps without excluders, and (3) excluders do not reduce the number of the largest-sized (and commercially most valuable) crabs that will be caught.

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Terrapins and Tires: Coastal Carnage at the Jersey Shore

Dana Ehret1, 2 and Kelly Hayes1, 3

1The Wetlands Institute, Stone Harbor, NJ
2Undergraduate Student at The Richard Stockton College of New Jersey, Pomona, NJ
3Undergraduate Student at Rowan University, Glassboro, NJ

Coastal development of barrier beach islands along the New Jersey shore has largely eliminated the formerly abundant sand dunes that are the natural nesting habitat of diamondback terrapins. The most readily available alternative nesting site has proven to be the embankments of roads crossing and adjacent to salt marshes. This is a very dangerous alternative. Every nesting season (late May or early June through mid July), hundreds of gravid females are killed or maimed by motor vehicles as they unwarily cross roads. During the nesting season, round-the-clock road patrols are sent out daily to remove live turtles from roads and to document road kills from which potentially viable eggs are removed for incubation. The onset of the nesting season and its length are quite variable. More road kills occur at night than during the day. Peak periods of mortality are almost always coincident with the increased volume of weekend traffic at this coasted resort area!

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Sonic Telemetry as a Tool for Natural History Observations
of Northern Diamondback Terrapins (Malaclemys terrapin terrapin)

William Espenshade

Research associate—The Wetlands Institute
Reptile House, the Philadelphia Zoo

Ring Island (Wetlands Institute) diamondback terrapins have been tagged with sonic telemetry transmitters. This study incorporates two goals. The first is to realize the utility of sonic telemetry as a tool for terrapin research. The second is to document natural history of this population of terrapins. Early observations indicated that terrapins at this study site move considerable distances within one tide cycle. Sonic telemetry has proved very effective at pinpointing exact terrapin locations.

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Terrapin Research in Southern New England

D. Gauthier, D. Gregson, D. Wiktor, R. Chambers, and M. Hill

Fairfield University, Fairfield, CT

Our group has been studying diamondback terrapins for the past four summers. We completed a population survey of terrapins from a marsh in Milford, CT during summer 1998 and 1999. Trammel nets strung across three different tidal creeks were used to capture and mark adult terrapins. In two years we had 182 captures with 70 recaptures, with 100% fidelity of recaptures to home creeks. In contrast, a similar study completed in Piermont Marsh on the Hudson River during summer 1997 yielded only eight terrapins with no recaptures. Because in some regions 95 percent of terrapin nests reportedly are lost to predators, during summer 2000 we initiated as assessment of nest predator exclosure devices in Great Meadows Marsh in Stratford, CT. To date, few female terrapins have used the exclosures as nesting areas. Nests in exclosures, however, have not experienced any predation, whereas over 30 nests surrounding the exclosures have been dug out by predators. Finally, we have begun an examination of terrapin genetic diversity in the region, using inter-simple sequence repeat (ISSR0 analysis of DNA isolates from terrapins collected from NJ, NY, CT, and RI. We expect our results will be useful in generating regional conservation plans for diamondback terrapins.

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Comparison of Fertility Rates and Hatchling Survivorship
of Field and Laboratory Incubated Nests

Maria Giamabco

Department of Biology, Hofstra University, Hempstead, NY

Long Island’s population of terrapins was severely impacted by exploitation from the mid-1800 through the 1930s. Since then terrapins have made a remarkable recovery but, the development of estuaries has resulted in a substantial habitat loss. Parks such as the Gateway National Recreation Area (GNRA) are vital nesting sites for these aquatic turtles due to this loss. However, the stability of these populations may be threatened by pollution and nest depredation. For this reason it is important to document the current fertility rates, emergence success and hatchling mortality of the population. To that end, eggs were collected from nests at Ruler’s Bar Hassock (part of GNRA) and incubated in the laboratory at temperatures ranging from 26°C–34°C. Hatchlings from these eggs will be raised in the laboratory to ascertain hatchling mortality and sex ratios. This data will be compared to data collected from nests that were protected in the field using wire-mesh excluder devices to prevent nest predation.

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Diamondbacks in North Carolina:
Insights from Terrapin Population Modeling, Radio telemetry,
and Mark-Recapture Efforts

Kristen Hart

Duke University Marine Laboratory, Beaufort, NC

Listed as a species of “special concern” in North Carolina, diamondback terrapin (Malaclemys terrapin terrapin) populations are declining due to habitat loss and anthropogenic mortality. Because we have only limited information on the population dynamics and distribution and abundance of terrapins within the state, I have focused my research questions and survey efforts at the population level. My goal is to delineate the full extent of their distribution within my study areas and determine the basic parameters of terrapin populations in this region. My specific studies center on population dynamics, population genetics, home range, habitat use, and seasonal movement of terrapins. To date, I have developed a general terrapin population model and calculated the first survival rates for adult terrapins. As a result of intensive fieldwork, I have documented the presence of 4 separate terrapin populations at individual sites in eastern North Carolina (in the region between Core and Pamlico Sounds). I conduct ongoing mark-recapture programs at each site and perform radio telemetry on terrapins at 2 of the 4 sites. I also collect blood samples from each captured terrapin for population genetics. In addition, I work closely with a local crabber on ways to reduce terrapin by catch in the North Carolina blue crab fishery. Modeling results indicate that protection of juveniles would benefit terrapin populations currently in decline. Results from the field so far indicate that overall terrapin population size in North Carolina is small and individual terrapins display extreme site fidelity from May to August. The intensity of threats varies per population but the three major problems for terrapins in this region of our state are crab pot mortality due to extensive interactions of terrapins with the commercial blue crab (Callinectes sapidus) fishery, road kill of gravid adult females, and habitat alteration and loss. Interesting findings include specific information on the spatial and temporal overlap of terrapins with the active commercial blue crab fishery in Jarrett Bay, clutch sizes and frequencies for female terrapins from the North River, amount of time a terrapin can remain in a crab pot before drowning, and the best place to draw blood from this unique reptile.

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Population Studies of Northern Diamondback Terrapins
(Malaclemys terrapin terrapin) on the Cape May Peninsula
of Southernmost New Jersey

Ted Hart1, 2 and Steve Emanuel1, 3

1The Wetlands Institute, Stone Harbor, NJ
2Undergraduate Student at University of Massachusetts at Amherst, MA
3Undergraduate Student at The Richard Stockton College of New Jersey, Pomona, NJ

Since 1997 we have been monitoring a terrapin population on Ring Island, adjacent to the Wetlands Institute. In the three major creeks (Bluefish, Mulford, and Ring Island) that drain this island, we have marked (using bar-coded microchips) over 700 terrapins of both sexes and varying sizes. Estimates of the total Ring Island population vary from about 800 to 3000. We have found virtually no movement of terrapins from one creek to another. And, over the course of this four-year study, there appears to have been a shift in the Ring Island population structure, with a perceptible decrease in the man size of females probably attributed to both continued road kill mortality and the introduction of increasing numbers of head-starters.

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Diamondback Terrapin Conservation Project in Southern New Jersey:
Recovery and Incubation of Eggs from Road Kills
and Head Starting of Hatchlings

Rosalind Herlands, Roger Wood, Jennifer Ciraolo, and Nichole Strickler

Biology Program, Richard Stockton College of New Jersey, Pomona, NJ

Since 1989, we have conducted a research and conservation project on the local northern diamondback terrapin (Malaclemys terrapin terrapin) population in the cape May Peninsula of New Jersey. Our goal is to offset partially the severe mortality of adult terrapins resulting not only form road kills but also from drowning in commercial crab traps. We recover eggs from road-killed females during the 5–6 week nesting season every June and July. Round-the-clock patrols on roads crossing and adjacent to salt marshes collect between 600–800 potentially viable eggs each season. The eggs are labeled by clutch and weighed and their length measured; they are then incubated in artificial nests of moist, coarse vermiculite in large plastic containers. The eggs are maintained under controlled temperatures, ranging from 26–32° C, in the laboratory facilities at Richard Stockton College. Between 33 to 50 percent of these eggs develop into fully formed hatchlings. These hatchlings emerge in 7–10 weeks. They are weighed and tagged and their carapace and plastron lengths are measured. The hatchlings are then “head-started” in our special “terrapin farm” until the following summer when they are released into their salt marsh habitat. In the last few years, we have successfully head-started and released over 85 percent of our hatchlings. Our success rate for hatching of these recovered eggs has been fairly consistent over the decade and we continue to find ways to increase this rate a bit each year. We are also developing additional steps to increase the survivability and health of the hatchlings that we release into their salt marsh habitat. This project has also given us the opportunity to study a number of interesting aspects of the biology of these turtles, such as their temperature-dependent sex determination, carapace anomalies, and growth patterns. Furthermore, the involvement of volunteers and elementary students in this project has increased local public awareness of this turtle’s threatened existence.

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Seasonal Abundance, Juvenile Habitat Preference,
and Mortality of Diamondback Terrapins (Malaclemys terrapin)
in the Jacques Cousteau National Estuarine Research Reserve
at Mullica River—Great Bay, New Jersey

R. Hoden and K. W. Able

Rutgers University Marine Field Station, Tuckerton, NJ

Diamondback terrapins (Malaclemys terrapin) were studied between May 1988 and September 2000 using various collection methods in both marine and terrestrial environments of the Jacques Cousteau National Estuarine Research Reserve at Mullica River—Great Bay, New Jersey. We collected diamondback terrapins in many major habitat types including open water near the shore in polyhaline bays, intertidal and subtidal creeks, and along Great Bay Boulevard (GBB) a road that runs through extensive Spartina alterniflora marshes. We focused our observations along GBB because of frequent daily access due to its proximity to the Rutgers University Marine Field Station. Adults (over 100 mm carapace length) occur along GBB beginning in June and extending through July. Hatchlings (25–35 mm) were most obvious in the spring with few individuals showing up in late summer. Juvenile terrapins (35–100 mm) were infrequently collected. Mortality rates on GBB due to automobiles were high during 1999. Of the total 121 terrapins observed 76.9 % were dead. Of these, 97 were hatchlings and 24 juveniles or adults with mortalities of 78.3% and 70.8% respectively. While we do not know the population size of terrapins in the study area, the large number of mortalities may have a significant effect if this annual estimate is representative. Laboratory observations on habitat preference for hatchling terrapins indicate that 91.7% were found in marsh peat vegetation as opposed to open water.

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Effect of Two Designs of Terrapin Excluder Devices
on the Catch of Blue Crabs in Commercial-Style Crab Pots

C. David Jenkins, Jr.,1 Paul G. Scarlett,1 and J. Richard Trout2

2Rutgers University, New Brunswick, NJ
1New Jersey Department of Environmental Protection, Division of Fish, Game and Wildlife, Trenton, NJ

We conducted experiments to evaluate the effects on the catch of blue crabs (Callinectes sapidus) by equipping crab pots with excluder devices designed to reduce the bycatch of diamondback terrapins (Malaclemys terrapin). The excluder devices tested were 5 x 15 cm wire rectangle and a 5 x 15 cm wire diamond. Equal numbers of each of three pot types (rectangular excluder, diamond-shaped excluder, no excluder) were deployed in the waters of Cedar Swamp Creek and the Mullica River—Great Bay Estuary, New Jersey, during late summer 1997 comprising a total of 934 pot-days. We evaluated the crab catch by examining the average size of crabs, the total number of crabs, and the number of crabs in various size classes using repeated measures analysis of variance. We found no evidence that either excluder affected the average size of crabs captured or the total number of crabs captured. The 5 x 15 cm diamond-shaped excluder reduced the number of crabs > 139 mm captured in the Great Bay trial, but not in the Cedar Swamp Creek trial or when the location data were pooled. We concluded that the 5 x 15 cm rectangular excluder represents an effective and economically efficient means of reducing an important source of adult mortality for diamondback terrapins without reduced catches for commercial crabbers. Continued refinement of the design of excluder devices is possible, and greater understanding of the spatial and temporal distribution of terrapins should help direct future modification of regulations requiring excluder devices on commercial crab pots.

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Proposed Educational Slide Set on Diamondback Terrapins

David S. Lee

The Tortoise Reserve, White Lake, NC

In 1999 the Tortoise Reserve in cooperation with the US Fish and Wildlife Service, the Baltimore Zoo and the Knoxville Zoo produced a slide set addressing the natural history and conservation needs of the bog turtle. The slide set is intended for educational use throughout the range of the species. It consists of 100 slides and a 20 page script covering the biology of the species, its habitat and habitat associates, zoogeography, and conservation concerns and their solutions. All funds generated from sales go directly to bog turtle conservation efforts. We propose producing a comparable educational slide set on diamondback terrapins. The format would be similar but a section on historical and commercial aspects of the terrapin would also be included. We expect to start this in the winter of 2000-01 and it will probably take about a year to complete.

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The Ecology and Demographics of the Diamondback Terrapin,
Malaclemys terrapin macrospilota and rhizophorarum in South Florida

Brian K. Mealey,1 Greta M. Parks,1 and Michael Forstner2

1Falcon Batchelor Bird of Prey Center, Miami Museum of Science, Miami, FL
2Dept. of Biology, Southwest Texas State University, San Marcos, TX

The ecology and population dynamics of Malaclemys terrapin subspecies are under investigation by collaborative investigators from many management, research, and educational institutions in south Florida. There are several concurrent methods applied in this study. The mark recapture study utilizes AVID microchips as a permanent marking system for all individuals encountered. Radio telemetry units from American Wildlife Enterprises are attached using Marin-Tex and have allowed this unique application of transponders in such strictly estuarine aquatic animals. DNA and serum mercury samples are collected from blood drawn from each individual.

The preliminary results indicate extreme site fidelity over this time period for female terrapins. Furthermore, survival of individual terrapins over a 15-year span has been documented using data from previous researchers in the region. Notably, these individuals are currently residing in the same highly localized environment in which they were first captured in the early 1980s. This is reflected in our results from radio telemetry (n=12 individuals) and mark recapture data. Furthermore, the analyses of mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) microsatallite markers support the physical evidence of limited dispersal. Comparison of the population of M. terrapin in Texas and Florida appear to indicate that overall smaller populations currently exist in Texas coast in otherwise comparable habitat. Florida terrapin populations represent localized assemblies with strong tendencies for long-term site fidelity. This has significant implications for management of these populations.

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Storm Mitigated Dispersal Events in Malaclemys terrapin

Linsay A. Miller1, John D. Baldwin1, Brian K. Mealy,2 Greta Parks,2 and Michael R. J. Forstner3

1Division of Biological Sciences, Florida Atlantic University, Davie, FL
2Miami Museum of Science, Falcon Batchelor Bird of Prey Center, Miami, FL
3Department of Biology, Southwest Texas State University, San Marcos, TX

This research project was undertaken to obtain current data on Malaclemys terrapin rhizophoraram in Florida Bay using mark and recapture techniques in conjunction with high resolution DNA markers to provide data management of this species. In order to manage and conserve an endangered animal such as Malaclemys terrapin, the dynamic of their populations must be understood. The most critical of the population parameters are population size, structure, demographics, and gene flow due to dispersal.

There are several hypothesized reasons for turtle dispersal including mating, nesting, search for food and fresh water, avoidance of habitat alteration, and major environmental effects such as hurricanes. It is well documented that a natural disaster such as floods, droughts, and hurricanes have forced many other species to disperse to new areas. Habitat destruction loss of shelter and food forces animals to disperse if they do not have the ability to acclimate to new environmental stresses. The primary focus of the project is to determine the effects, if any, of Hurricane Georges on M. t. rhizophorarum. September 15th through October 1st, 1998, Hurricane Georges swept through the western Atlantic Ocean and Gulf of Mexico devastating coastal communities in its path. Although Hurricane Georges caused severe habitat destruction in the Florida Keys, it is unclear as to whether local groups of M. t. rhizophorarum remained intact in their pre-Hurricane Georges locations within Florida Bay. Virtually no immigration and emigration between keys has been previously seen in Malaclemys subpopulations within Florida Bay. Hurricane mitigated dispersal of terrapins can be detected by mark and recapture data and by comparison of previously collected mitochondrial DNA and microsatellite data to samples collected post hurricane Georges. Mark and recapture data that indicates movement, as well as new allele frequencies in the subpopulations post Hurricane Georges, would indicate gene flow, and therefore dispersal. Preliminary results indicate that while individuals at the study sites retain high fidelity, new individuals and new allelic forms are seen after the passage of such a major storm.

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Preliminary Status of Diamondback Terrapins
in the Vicinity of Mobile Bay, Alabama

David H. Nelson,1 John J. Dindo,2 and Roger C. Wood3

1University of South Alabama
2Dauphin Island Sea Laboratory
3The Wetlands Institute and The Richard Stockton College of New Jersey

A consortium of interested parties in coastal Alabama recently organized itself to study the status of terrapins (Malaclemys terrapin pileta) in the vicinity of the Mobile Bay. Our goal was to establish the distribution and abundance of terrapins, as well as to promote the conservation of this beleaguered species. Terrapins in this region have not been previously studied. Conversations with local fishermen and biologists, preliminary field reconnaissance and some limited photographic documentation have established the presence of terrapins in a number of different localities. In one preliminary study at the airport salt marsh on Dauphin Island, 9 hatchlings were observed, marked and released, although no turtles were captured in 12 crab traps over an 8-week period in June and July 2000. It appears that increased terrapin activity here may occur during the early spring (March and April).

In another preliminary study, 12 modified crab traps were set out in salt marshes of Weeks Bay for 51/2 weeks during July and August 2000. No diamondback terrapins were ever encountered there. Discussions with crabbers, fishermen, and state biologists confirm that terrapins are captured in crab traps along coastal Alabama. Field trips to potential nesting sites disclosed nest predation at Port Aux Pines, Heron Bay and Coffee Island. Terrapins are present in a number of localities. However, the full extent of their distribution within the study area, as well as the basic parameters of the population in this region, remain to be determined. Meanwhile, free terrapin excluders are being offered to any commercial and recreational crabbers willing to use them.

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Predators and Predation Rates at the Jamaica Bay Wildlife Refuge

Sylwia Ner

Department of Biology, Hofstra University, Hempstead, NY

The Jamaica Bay/Breezy Point Unit (JB/BPU) is one of the four management units of The Gateway National Recreation Area (GNRA). Ruler’s Bar, the largest island of JB/BPU, has been the main area of terrapin studies in GNRA so far. A raccoon population appears to be established in Ruler’s Bar Hassock since the 1980’s and is now destroying 92% of terrapin nests. I have begun surveying the seven other upland islands within JB/BPU, in an attempt to learn more about important nesting beaches and how predation rates vary between them. The seven islands are: Elder’s Point, Pumpkin Patch, Subway Island, Ruffle Bar, Canarsie Pol, Little Egg Marsh, and the already studied Ruler’s Bar Hassock. These islands differ in size, proximity to the mainland, and, very likely, both mammal and bird inhabitants. I will compare predation rates on the islands occurring on islands to predation occurring in different parts of GNRA. I am planning to survey the birds and mammals of these islands to document potential and actual nest and adult predators.

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Population Study of Northern Diamondback Terrapins
in Hundred Acre Cove, Barrington, Rhode Island

E. Douglas Rayner and Charlotte B. Sornboger

Members of the Barrington Land Conservation Trust

An accounting of the population of Northern Diamondback Terrapins has been conducted for the last 11 years in the Hundred Acre Cove area, one of the largest salt marsh expanses in our state. This is the last remaining colony of terrapins in Rhode Island. We believe we now have a good idea of the number of individuals in the colony and the extent of their range.

The aim of the study has been to create a wildlife area (the 70 acre “Doug Rayner Wildlife Refuge at Nockum Hill”) sufficient for their nesting requirements and to protect them in the cove (speed limits on motor boats). We have come to understand that their successful protection will need to be an ongoing awareness on the part of the residents here.

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The Role of Micro and Macro Environmental Variation
on Nest Success of the Diamondback Terrapin

Willem M. Roosenburg

Ohio University, Department of Biological Sciences

The estuarine turtle Malaclemys terrapin, nests on narrow sandy strips that border Chesapeake Bay. Most nesting areas are elevated slightly above the mean high tide. As a result, the environmental conditions during the nesting seasons determine the length of the incubation period and this the exposure of developing embryos in this precarious habitat. I will present long-term demographic data that suggests annual variation in recruitment and sex ratio is determined primarily by temperatures during July, when most nests go through their sex determining stage. Warmer July temperatures result in shorter incubation times that increases survivorship because hatchlings emerge before the autumnal spring high tides inundate nests and drown embryos. Furthermore, microhabitat variations on nesting habitats are being altered by stabilization techniques such as bulk heading, rip-raps and planting of beach grasses. I will present data of nesting frequency and nest success from a section of shorelines that was stabilized in a “terrapin friendly” manner. I suggest that terrapin conservation requires the preservation and maintenance of a diverse set of nesting beaches to maintain local populations, and that the technology available be applied to accommodate the nesting needs of terrapins while stabilizing shoreline.

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Diamondback Terrapin Conservation
and Habitat Management in Maryland

Kevin Smith1 and Marguerite Whilden2

1Department of Natural Resources, Coastal and Riparian Restoration
2Department of Natural Resources, Fisheries Service

Despite its previous status as one of the State’s most valuable fishery, the diamondback terrapin has been scarcely noticed in recent years by fisheries and wildlife managers. Despite a decade’s long focus on fisheries and non-structural shore erosion measures, the public has not embraced the concept nor the approach to maintaining Maryland’s shorelines. Beginning in 1998, the State of Maryland developed a comprehensive terrapin conservation program in cooperation with the habitat restoration efforts from within the Department and other federal and non-government organizations. The terrapin, its history and its nesting habitats provide the ideal platform for a conservation and stewardship effort. The terrapin allows us to cast a wide net in all levels of interests and natural resource issues. In two years since the initiation of the State’s comprehensive terrapin conservation and habitat management efforts, i.e. Terrapin Station, significant conservation, research, public information, stewardship, partnerships, cooperation, communication, and species specific habitat restoration and monitoring.

This presentation will discuss the breadth of the State’s terrapin conservation effort, the traditional and non-traditional methods employed, the accomplishments of the program thus far, and the concerns for the future efforts in Maryland and other states

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Home Range, Habitat Selection, and Diet of the Diamondback Terrapin
(Malaclemys terrapin) in a North Carolina Estuary

Phil Spivey

Georgia Department of Natural Resources Nongame Wildlife Section

We used radio telemetry to track 29 adult diamondback terrapins to estimate home range and examine habitat selection in a ditched North Carolina estuary (Carteret Co.). Pooled telemetry observations revealed terrapins selected areas of low, frequently flooded marsh over high, infrequently flooded marsh habitats. Overall, natural creeks in the study area were not used as often as areas of ditched marsh, possibly a result of intensive commercial crabbing efforts in the creeks. Eighty-six percent of all telemetry locations were within ditched marsh. Average home range was 257.7 ha (range 50.6-427.7 ha) as calculated by the adaptive kernel method.

We investigated the diet of the diamondback terrapin during the spring and summer of 1997. Large-sized (>30mm head width; n=14) terrapins consumed 75% blue crabs (Callinectes sapidus) consisting of whole juvenile crabs (60%) and cropped limbs (15%) of larger crabs. For medium-sized terrapins (20-30mm head width; n=20), 31% of their diet was fiddler crabs (Uca pugnax) in addition to 62% juvenile blue crabs. The diet of small sized terrapins (<20mm head width; n=34) consisted of 68% eastern melampus snails (Melampus bidentatus). Significant dietary overlap existed between medium and large terrapins. Large terrapins had the most diverse diet being comprised of 11 prey species. Small terrapins were most specialized, with only 4 prey species.

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Health Assessment of Captive Raised and
Wild Diamondback Terrapins (Malaclemys terrapin)

Ralph E. Werner V.M.D.,1, 3 Dana Ehret,2, 3 and Lisa Jensen2

1Research Associate—The Wetlands Institute, Stone Harbor, NJ
2The Wetlands Institute, Stone Harbor, NJ
3The Richard Stockton College of New Jersey

In recent years there has been growing concern over the possibility of disease transmission when captive raised or rehabilitated animals are released into a wild population. For over a decade, Richard Stockton College has been raising and releasing diamondback terrapins into the Cape May county marshes. This study looked at various health parameters in both captive raised and wild terrapins to see if any diseases existed in either cohort. Both populations appeared to be relatively free of parasites or overt disease. The conclusion is that the releases of captive raised turtles is not a health threat to the native terrapins, nor are the wild turtles a source of disease for the released hatchlings.

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Field Studies of Mangrove Terrapins
(Malaclemys terrapin rhizophorarum) in the Florida Keys

Roger C. Wood

Research Director—The Wetlands Institute, Stone Harbor, NJ
Biology Department of The Richard Stockton College of New Jersey, Pomona, NJ

In the early 1980s I initiated field studies of the previously neglected mangrove terrapin. There are two morphologically discrete terrapin populations in the Florida Keys. The southern population is the true mangrove terrapin. The northern population, in Florida Bay, represents a previously undescribed subspecies. The distribution of terrapins in the Keys is patchy, with denser populations occurring in Florida Bay than in Key West National Wildlife Refuge. Terrapins do not hibernate in the Florida Keys, and there is evidence suggesting that their activities may be primarily nocturnal.

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