Author(s): Maryam Farzadkhoo; Richard Kingsford; Iain Suthers; John Harris; William Peirson; Stefan Felder
Keywords: Ttraction velocity; Fish movement trajectory; Fish migration; Turbulent kinetic energy; TKE; Juvenile fish
Abstract: Natural rivers have been significantly fragmented by barriers that impede fish migration, leading to a rapid decline in abundance of some freshwater fish species. To remediate the regulated river regimes, fishways are essential to facilitate fish migration. The Tube Fishway allows the lifting of fish at near-atmospheric pressure across barriers >100 m. A key part of the Tube Fishway’s operation is the attraction of fish into the transfer chamber via a slotted entrance. Recent laboratory research has shown that silver perch (Bidyanus bidyanus) and Australian bass (Percalates novemaculeata) can be successfully attracted by velocity of 0.15 m/s. However, a better understanding of interaction between attraction flows and the rheotactic behavior of fish is needed. New experiments investigated the response of fish to hydraulic parameters (velocity and turbulent kinetic energy) in the flow region downstream of the transfer chamber’s entry slot. The flow resembled jet flows which was concentrated across a small section of the entry zone. The majority of fish followed the jet flow trajectory with higher velocity and turbulent kinetic energy on their way into the transfer chamber. This finding provides important guidance for the effective operation and further optimization of attraction of juvenile fish into Tube Fishways.