OBSERVATIONAL ANALYSES FOR DIAMONDBACK TERRAPIN (Malaclemys terrapin) AND BLUE CRAB (Callinectes sapidus) BEHAVIOR ASSOCIATED WITH TRAP ENTRY IN THE BLUE CRAB FISHERY

Johnson, Janelle

OBSERVATIONAL ANALYSES FOR DIAMONDBACK TERRAPIN (Malaclemys terrapin) AND BLUE CRAB (Callinectes sapidus) BEHAVIOR ASSOCIATED WITH TRAP ENTRY IN THE BLUE CRAB FISHERY

Authors

Johnson, Janelle

Abstract

Bycatch is an issue faced by many fisheries. Local populations can suffer considerable negative impacts resulting from bycatch mortality. One bycatch issue in South Carolina is the drowning of diamondback terrapins, Malaclemys terrapin , in commercial style crab traps deployed to capture the Atlantic blue crab, Callinectes sapidus . This study examined behavior associated with entry into traps for both species to test the efficacy of different bycatch reduction device (BRD) designs and orientations at reducing terrapin entry while maintaining blue crab entry, as well as to determine if terrapin presence in a trap would deter blue crab entry. Direct observations allowed quantification of effort and ability of both species to enter a trap. When BRD dimensions are appropriately scaled, they can significantly reduce terrapin capture without significantly decreasing blue crab capture in a controlled setting. Orientation of the BRD had no significant effect on the ability of neither male terrapins nor male blue crabs to enter traps. In addition, terrapin presence had a negative effect on blue crab entry into a simulated trap. Future behavioral and field studies can lead to a better understanding of other factors that influence terrapin and blue crab interactions in and around crab traps.