EFFECTS OF VEGETATION DENSITY ON SWIMMING BEHAVIOR OF ZACCO PLATYPUS

Abstract

 It is important to secure the rest area for fish. Fish has the ordinary and dark muscle. When fish uses ordinary muscle, fish gets tired. In such a situation, fish needs a rest. In this study, vegetation density in open-channel is changed. The trajectories of Zacco platypus's were observed. It was found that Zacco platypus utilized a slow of the speed as rest space. Stay in vegetation area increases with an increase of vegetation density. An approach rate to vegetation area rises with an increase of vegetation density. However, It was not found that clear relationship with a migration rate of Zacco platypus and vegetation density.