Development of a Fish Behaviour Model in Coastal Sea

Abstract

The evaluation of the behaviours of fish which stand on higher levels of food-web 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, Pagrus major 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, prey density, 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 east Seto Inland Sea. As a result of the simulations, it is clarified that the both water temperature and prey density have large influence on migration and distribution of Pagrus major.