The impact of commercial crab traps on northern diamondback terrapins, Malaclemys terrapin terrapin

Wood, R.C.
Journal/Publisher Name
Proceedings: Conservation, Restoration, and Management of Tortoises and Turtles-An International Conference
Page #s
Contact information
Richard Stockton College of New Jersey, Pomona, NJ 08240

Several versions of a terrapin excluder design were tested on crab traps to determine how effective they were in reducing terrapin bycatch and what the effect on catch rates of targeted crabs was. All tests consisted of modified and unmodified traps being set in an alternate fashion. A wire bar placed across the opening of the traps was unsuccessful in reducing terrapin bycatch. A second design, which was a rectangular frame (5x10 cm) was successful. Standard traps caught 13 out of 15 terrapins during 1992 and 46 out of 51 during 1995, with the remainder of terrapins being caught by traps modified with the frame. Additional testing of the rectangular frame size, determined the 4.5x10 cm frame reduced terrapin bycatch the most (22 terrapins caught in unmodified vs. none in modified traps). Additionally, crab catch rates were 9% higher in the modified traps (4.5x10 cm) compared to the unmodified traps and crabs were of similar sizes in the two traps. In comparison, crab catch rates were 11% higher than in the unmodified traps when the 5x10 cm excluder design was used in 1994 (multiple sites) and 49% higher in 1995 (single site).