Marine Fisheries Research and Development Center (JAMARC) of Fisheries Research Agency, Yokohama, Kanagawa 220-6115, Japan
Red tilefish Branchiostegus japonicus is the main target species of bottom longline fisheries in the East China Sea. To explore methods of optimizing utilization of the resource by protecting small fish, TL compositions were analyzed using logistic regression analysis. Fishing region, year, season and sex of the species were used for explanatory variables. The model selection by using Akaike's information criterion (AIC) indicated that the best fit model includes all the explanatory variables. The fishing region had the largest effect. Small individuals tend to be distributed in higher abundance in the northeastern and western regions of the continental shelf. The results of the analysis indicate the possibility of a management strategy for protecting small fish by closing fishing regions where small fish are predominant.