A STUDY ON THE OPERATION STRATEGIES FOR BOTTOM OTTER TRAWLING IN ISE BAY

摘要

In order to simulate the bottom trawl fishery in Ise Bay, a typical semi-enclosed bay in Japan, a fishery simulator has been developed that consists of a fish behavioral model and a fishing operations model. The fish behavioral models are developed for two major target species, conger eel and mantis shrimp, which consider the fish migration as well as the growth and the population change. The fish behavioral models are combined with a fishing operation model, which predicts the behavior of trawling boats based on economic conditions and resource distribution as well as the fish catch amount by each boat. The model is applied to evaluate the effects of fishery management, and it is investigated that how the control of fishing efforts or number of owned fishing boats affects the profit of the target fishery. The mesh size of the trawling net which maximizes the total catch is estimated considering both conger eel and mantis shrimp. At the target ports, reduction of boats number will increase the profit because the effect of fixed cost change exceeds the impact of fish catch decrease. However, the optimum reduction rate is different in each port and interactive effect should be also considered.