Development a behavioral model of Conger myriaster in Ise Bay

The evaluation of the behaviors of fish which stand on higher trophic level is important from the viewpoint of the resource management or other environmental impacts. Especially for the adult fish which can swim against the currents of circumference, considering the migration effects in the model is quite significant. In the present study, a fish model is developed which considers the migration effect by modeling the preference for the environmental factors. As the target fish of modeling, Conger myriaster is chosen because it is one of the representative species due to its high resource value. In the model, the direction of the fish movement is determined by the preference strength for the environmental factors such as water temperature, dissolved oxygen, and so on. The model is coupled with a hydrodynamic model and a lower-trophic ecosystem model which predict physical environment and water quality of the target area. Numerical simulations are carried out to reproduce the spatial distribution and seasonal variations of ecosystem in Ise Bay. The major features of environmental conditions such as variability of water temperature and behavior of oxygen deficient water were well reproduced. The results of fish behavior simulation showed that the area with high resource density in the simulation correspond to high CPUE area in the real world. It is also clarified that the dissolved oxygen has large influence on migration and distribution of Conger myriaster in summer season and the effect of water temperature is dominant in winter.