Biological and Operational Factors Causing Mortality in North Carolina's Soft-Shell Blue Crab Industry

Abstract

Factors causing mortality in North Carolina's soft-shell blue crab industry were quantified and identified at 11 crab shedding systems across the state. Operators of crab shedding systems who shed peeler crabs (pre-molt crabs) that they had caught themselves (self-caught peeler crabs) experienced significantly lower crab mortality rates than operators who shed peelers that they had bought from different sources (purchased-peeler crabs). Molt stage had a significant effect on the mortality rates of self-caught peeler crabs, as early molt stage crabs (white-line peelers) suffered significantly higher mortality rates than late molt stage crabs (red-line peelers). Purchased male crabs experienced significantly higher mortality rates than purchased females crabs. Water quality did not have a significant effect on crab mortality. Male peeler crab mortality was not significantly affected by the presence or absence of female red-line peeler crabs. Male red-line peelers experienced significantly longer times to molt when male crab density was high. Results of this study may lead to improvements in crab shedding technology, increased profits, and better fishery management practices.