An evaluation of the effects of blue crab (Callinectes sapidus) behavior on the efficacy of crab pots as a tool for estimating population abundance

摘要

Crab traps have been used extensively in studies on the population dynamics of blue crabs to provide estimates of catch per unit of effort; however, these estimates have beenuddetermined without adequate consideration of escape rates. We examined the ability of the blue crab (Callinectesudsapidus) to escape crab pots and the possibility that intraspecific crab interactions have an effect on catchudrates. Approximately 85% of crabs that entered a pot escaped, and 83% of crabs escaped from the bait chamberud(kitchen). Blue crabs exhibited few aggressive behavioral interactions in and around the crab pot and wereuddocumented to move freely in and out of the pot. Both the mean number and size of crabs caught were significantlyudsmaller at deeper depths. Results from this study show thatudcurrent estimates of catch per unit of effort may be biased given the high escape rate of blue crabs documentedudin this study. The results of this paper provide a mechanistic view of trap efficacy, and reveal crab behavior in and around commercial crab pots.