UPSTREAM MIGRATING ROUTE OF JUVENILE AYU IN A MODIFIED LARINIERPASS FISHWAY

Abstract

kept smooth. The Larinier pass was modified for juvenile ayu, the formation of resting pools at close intervals and timber baffles with a slit on both sides. The fishway was experimentally installed to investigate biological evaluation in a hydraulic laboratory and on a divergent weir in Sendai river in Tottori Prefecture. The lower velocities take place along both sides to guide juvenile ayu. Local velocities are in the range of sustained speeds or in the range of their burst speed that cannot be maintained for a long time. It is pointed out for juvenile ayu that the formation of resting pools at close intervals should be provided to sustain upstream migrating route.