Abstract
The ayu is one of the most important fish for fishery in Japan so that it is necessary to conduct the environmental assessment before construction of the hydraulic structures in the river. Some parameters such as hydraulics and water quality may influence on habitability for the ayu. However, it is not known that what kind of parameter is effective on habitability for the ayu. In this study, a statistical analysis, such as a cluster analysis and principal component regression analysis, was conducted by using of 42 Aclass river data. As a result, the haul of ayu can be predicted from the hydraulics and water quality. It was found that 14mg/L (SS) and 3mg/L (BOD) were the limitations of habitat condition for the ayu.
