Size selectivity of trap for male red queen crab Chionoecetes japonicus with the extended SELECT model

A series of comparative fishing experiments was carried out in waters off t he east coast of Korea in 1997, using traps of six different mesh sizes (95 , 112, 122, 132, 152, and 172 mm mesh opening) to determine the size select ivity of a conical trap for male red queen crab, Chionoecetes japonicus. Th e extended SELECT (Share Each LEngth's Catch Total) analysis method was app lied with fishing effort data to obtain trap size selectivity, with a symme tric logistic equation used to express selectivity curves. Traps of 95 mm m esh size were employed as the control gear in the analysis. Logistic and sp lit parameters of each mesh-size trap in the SELECT model were calculated b y the maximum likelihood method. The model of split parameter p fixed with equal fishing efficiency, was chosen from the likelihood ratio tests and Ak aike's Information Criterion (AIC) comparison. From the determined logistic parameters, the carapace widths of 50% retention were estimated to be 82, 85, 92, and 101 mm for 122, 132, 152, and 172 mm mesh-size traps, respectiv ely. The selectivity curves of each mesh-size trap showed that traps of lar ger mesh size allowed more crabs of small carapace width and low commercial value to escape.