Hydraulics driven upstream migration of taiwanese indigenous fishes in a fish-bone-type fishway

摘要

Discharges of 0.016, 0.032, 0.048, 0.075, 0.1, and 0.15 m(3)/s in a fish-bone-type fishway were employed to analyse its complex hydraulics for fish migration. Four swimming and three leaping and climbing species endemic to Taiwan migrated upstream along the fishway, and their swimming speeds, migration ratios, and pathways were observed. The swimming species all had migration ratios above 50 %; a hemp rope helped the other fishes and algae shrimps migrate at low discharge. The fishway proved suitable for all the considered species, except for the leaping and climbing species which needed a hemp rope to successfully migrate. Computational fluid dynamics modelling explained the observed complex flow fields, and supported the observed velocities and flow depths. Additional numerical results such as turbulence in the fishway are also discussed.