EVALUATION OF FISH MIGRATION SUCCESS THROUGH FUSHINO RIVER STONES EMBEDDED FISHWAY BASED ON PREFERENCE

Abstract

 Stones embedded fishway in Fushino river is highly appreciated as an good example of inexpensive small scale restoration works. However, its efficiency on fish migration and/or designing parameters of the same type of fishway are not clear enough. To examine the migration efficiency of the fishway, we released Ayu (Plecoglossus Altivelis Altivelis) in the fishway and measured migration success rate. We also built an fishway evaluation procedure based on fish preference on velocity and air bubble. The evaluation procedure could successfully explain 30 min migration success rate. To improve migration success rate in a fishway which has multiple migration paths, not only preparing highly preferred migration paths, but also removing less preferred migration paths would be important.