Factors driving the density of derelict crab pots and their associated bycatch in North Carolina waters


Voss, Christine M., Joan A. Browder, Andrew Wood, and Adriane Michaelis
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Lost or derelict fishing gear can impair fisheries by contributing to the depletion of target species populations and can reduce nontarget fish and wildlife populations. We measured the density of derelict crab pot (DCPs) using side-scan sonar and examined bycatch associated with DCPs in nearshore waters (depths ≤4 m) of 6 waterbodies important to the North Carolina blue crab fishery, the state’s most valued commercial fishery. Extrapolated mean DCP density was 105 DCP/km2 of open water (range: 6–301). Densities of DCPs differed significantly among waterbodies but not among habitats (marsh creeks, estuarine edge ≤50 m from shore, and Atlantic Intracoastal Waterway margin). Extrapolated DCP densities were generally greater than those concurrently observed for actively fished crab pots within the 201 1-km2 cells sampled during 23 survey days between April and November 2010. Of the DCPs examined, 41% contained bycatch (unintentional catch) and 37% remained capable of trapping organisms. Bycatch was dominated by blue crab (Callinectes sapidus) and Florida stone crab (Menippe mercenaria) and included 5 diamondback terrapin (Malaclemys terrapin) and 1 clapper rail (Rallus crepitans). Based on monitoring of four 1-km2 cells, annual DCP “recruitment” was 1.5 DCP/km2 (1 SD). Reducing recruitment, persistence, and entrapment capability of DCPs would benefit the blue crab and Florida stone crab fisheries, as well as help conserve at-risk wildlife populations.