Use of a vertical‐slot fishway by galaxiids in Western Australia

Abstract

Abstract – The Goodga River Fishway is the first vertical‐slot fishway in Western Australia and was opened in April 2003 with the aim of increasing the habitat available to two galaxiids; the trout minnow (Galaxias truttaceus), a highly restricted freshwater fish species in Western Australia, and the widespread common jollytail (Galaxias maculatus). The fishway was designed to function during low flows to coincide with the upstream spawning migration of G. truttaceus. Prior to the opening of the fishway, no fish were found above the Goodga River gauging station (weir), which is approximately 2 km upstream of the river's entrance to Moates Lake. Fish migrations were monitored in each season between April 2003 and February 2005. Galaxias truttaceus utilised the fishway in all sampling periods. Adult fish migrated up the fishway prior to spawning, while large numbers of new recruits (small juveniles) negotiated the fishway during November 2003 and 2004. More G. truttaceus and G. maculatus were captured on the fishway during daylight hours compared with the night; however, larger G. truttaceus were more commonly captured at night whereas G. maculatus on the fishway were larger during the day. The fact that fishway utilisation by G. maculatus was consistent during all samples and new recruits migrated during periods of low flow demonstrates the importance of understanding the migration patterns of the target species when designing fishways.