EFFECTS OF BOTTOM TRANSVERSE SLOPE OF POOL-AND-WEIR FISHWAY ON MIGRATION RATE OF OPSARIICHTHYS PLATYPUS

Abstract

 In order to ensure high migration rate in fishways, it is necessary to understand the optimal shape of the fishway. In this study, effects of bottom transverse slope of pool-and-weir fishway on migration rate of Opsariichthys platypus were investigated by changing the transverse slope and the flow velocity over the notch. As a result, migration rate of Opsariichthys platypus increases with an increase of the flow velocity when the transverse slope is positive. This indicates that the fish prefer to orient in the high depth and low flow velocity zone before migration, and that the distance between the notch and orientation area is close.