A model of fish distribution in rivers according to their preference for environmental factors

We present a model of fish distribution according to the fish preference for environmental factors such as water temperature, cover, current velocity, turbidity, food amount, etc. This model can be used to estimate the influence of nearshore construction activity on fish. Our model has the good feature that the parameter values for the environmental preference and the weight values of the environmental factors can be determined separately. New environmental factors can be introduced without calibrating the preference parameters again. In our first experiment, two separate tanks with different environmental conditions are connected by a narrow junction. Fish can swim to the tank they prefer and their distribution is recorded by a video camera every minute for 50 min. The parameters are calibrated according to these observations. The second experiment uses a single tank where several environmental conditions are tested simultaneously. The observed fish distribution in the second experiment and the distribution calculated with the model show a good agreement. Finally, this model is included in the Shallow Sea Ecological Model (SSEM), and fish behavior in a virtual river is simulated to replicate fish distribution during a flood.