Abstract
The unexpected migrations of some living things are caused by the intake and withdrawal from river and lakes. Particularly serious are problems with fish straying from their normal migratory routes.
It is expected that a method in which small pieces of colored cloth are allowed to drift in a flow will be effective in preventing fish from straying. In this paper, some prevention methods are examined through experiments. The authors also seek to clarify the behavior of these fishes, especially Ayu by combining the numerical analysis for the flow, and the random walk method for the behavior of fishes. As a result, the prediction of the behavior of fishes is now possible. And using the numerical methods the authors present some methods for preventing Ayu from straying.
