EFFECTS OF BOTTOM SLOPE IN POOL-AND-WEIR FISHWAY ON MIGRATION RATE OF AYU, PLECOGLOSSUS ALTIVELIS ALTIVELIS

Abstract

 Understanding appropriate geometric configuration is required when pool-and-weir fishway with high migration rate is set up. Almost its bottom slope is horizontal on existing them and the past study. However, there is no study for effect of the bottom slope in pool-and-weir fishway on migration rate. In this study, effect of bottom slope in pool-and-weir fishway on migration rate of ayu (Plecoglossus Altivelis Altivelis) by changing flow velocity and bottom slope was investigated. It was found that the migration rate become high value when the bottom slope was set low toward downstream side wall to upstream one. It is because migration route is short in this bottom slope.