The Effect of Discrete BRDs on Crab Captures and Terrapin Exclusion.

Diamondback Terrapins are a smaller sized turtle that lives in the coastal waters from New England to Texas. They are known to enter crab traps and drown, and this issue could be major conservation concern. In Florida, there is a need to reduce terrapin by-catch mortality while maintaining the capture of large sized blue crab. We are teaming up with our partners at FWC to examine this issue comprehensively.

Several studies have attempted to understand the effects of crab fishing on terrapins with an emphasis on testing by-catch reduction devices (BRDs) to reduce terrapin mortality. However, the use of BRDs have not been required in most states, possibly due to concerns over crab capture sizes and rates. Several BRD types have been proposed. For example, the 5 x 10 cm BRD proposed by Wood (1997) is slightly more restrictive than the 5.1 x 15.3 cm BRDs used in New Jersey and New York. However, in Delaware, Maryland, and Virginia a smaller BRD (4.5 x 12.1 cm) is used on recreational crab traps. Arendt et al. (2018) used modeling techniques to design and test a 5.1–6.4 x 7.3 cm BRD, which may be more effective at capturing legal sized crab while maintaining terrapin excluding potential. This project will utilize modeling techniques and an experimental component to determine the effectiveness of different BRD types on terrapin exclusion while maintaining crab captures.