Terrapins and Traps
Diamondback terrapins are small, harmless turtles that are only found in salt marshes of the Atlantic and Gulf coasts of the United States. Throughout much of their range, terrapin numbers have been declining (Mann, 1995; Seigel and Gibons, 1995; Wood, 1997).
Part of the reason for this decline is the increasing use of commercial crab traps for commercial and recreational purposes in the same salt marsh creeks and sounds where terrapins dwell. This is a problem not only in New Jersey but also in other areas where terrapins occur (Bishop, 1993).
In New Jersey, a maximum of 27,565 commercial crab traps were reportedly in use in 2001. This number does not include unreported commercial crab traps or recreational traps also in use. Commercial crab trap use is even more intensive in other states. For example, some 650,000 crab traps are annually set along Louisianas coast (Arcement and Guillery, 1993).
In view of all the foregoing facts, a new regulation has gone into effect in New Jersey as of January 1, 1998. This regulation states that all commercial-style traps used in waters less than 150 feet wide at low tied or in any man-made lagoon must be fitted with devices designed to exclude diamondback terrapins. These devices may be either rectangular or diamond shaped and no longer than 6 inches wide or 2 inches high. These devices should be attached across the opening at the narrow end of each funnel entrance. This regulation is intended to protect an increasingly threatened natural resourcediamondback terrapinswithout detrimentally affecting the catch of New Jersey's crabbers.
The reason that traps fitted with excluders are only required to be used in certain situations is a reflection of the nonuniform distribution of terrapins in coastal waters. Terrapin populations are densest in salt marsh creeks and near marsh banks fringing the open waters of sounds and bays. Terrapins are less abundant in open waters, and are thus somewhat less likely to be caught in crab traps set in these areas.
Moreover, it is the intent of this regulation to require virtually everyone who uses commercial-type traps for recreational purposes (and the best available estimates are that there may be 10,000 or more traps annually used by recreational crabbers in New Jersey) to fit their traps with terrapins excluders. (Note: The regulation discussed here pertains only to the use of commercial crab traps. Crab traps designed solely for recreational use, with sides that flip up when the trap cord is pulled, do not drown terrapins and are not governed by this regulation.
First Aid for Trapped Terrapins
Terrapins can survive for longer under water than humans can because turtles are cold-blooded animals. No one knows precisely how long an active terrapin (as opposed to one hibernating in the winter) can survive under water probably several hours at least, but certainly less than a full day. It is essential that all commercial crab traps be checked at least once a day. Otherwise, all trapped terrapins will drown.
Arcement, E. and Guillory. 1993. Ghost fishing in vented and unvented blue crab traps. Proceedings of the Louisiana Academy of Science 56:17.
Bishop, J. H. 1983. Incidental capture of diamondback terrapins by crab pots. Estuaries 6(4):426430.
Mann, T. M. 1995. Population surveys for diamondback terrapins (Malaclemys terrapin) and Gulf salt marsh snakes (Nerodia clarkii clarkii) in Mississippi. Mississippi Museum of Natural Science, Technical Report No. 37. 75 pp.
Siegel, R. A. and J. W. Gibbons. 1995. Workshop in the ecology, status, and management of the diamondback terrapin (Malaclemys terrapin), Savannah River Ecology Laboratory, 2 August 1994: final results and recommendations. Chelonian Conservation and Biology 1(3):240243.
Wood, R. C. 1997. The impact of commercial crab traps on northern diamondback terrapins, Malaclemys terrapin terrapin. In J. Van Abbema (ed.), Proceedings: Conservation, Restoration, and Management of Tortoises and TurtlesAn International Conference, pp. 2127. A joint publication of the New York Turtle and Tortoise Society and The Wildlife Conservation Society Turtle Recovery Program. 494 pp.