Can a low-gradient vertical-slot fishway provide passage for a lowland river fish community?
Australia, carp, design, efficiency, entrance, fish movement, fishways, perch, PIT tag, regulated rivers, transponder, trapping, turbulence, upstream, vertical slot, water velocity
Journal or Book Title
Marine and Freshwater Research
Fishways are commonly used to restore native fish movements in regulated rivers. In the Murray-Darling Basin, Australia, 14 fishways are to be built by 2011 to improve passage along 2225 km of the river. The first of these fishways, constructed in 2003, is a vertical-slot design with low water velocities (0.98-1.4 m s(-1)) and turbulence (average 42 W m(-3)). This design was selected to provide passage for individuals between 20 and 1000mm long. To determine passage success, trapping and a remote automated passive integrated transponder (PIT) tag reading system was used from October 2003 to February 2006. In 57 24-h samples at the exit (upstream end) and entrance (downstream end), 13 species and 30 409 fish were collected at a maximum rate of 4415 fish per day. Fish between 31 and 1030 mm successfully ascended the fishway. However, significantly smaller (<31 mm) fish and small-bodied (<50 mm) carp gudgeons (Hypseleotris spp.), a species previously considered non-migratory, were sampled downstream from the entrance of the fishway. The remote PIT tag reading system revealed that 81% of native golden perch (Macquaria ambigua) and 87% of non-native common carp (Cyprinus carpio) successfully ascended the fishway. These data will help maximise the efficiency of future fishways against a series of pre-determined performance criteria.