Stimulating fish passage through managed flows in the Wakool River system
Wooden, I. and Baumgartner, L., 2011. Stimulating fish passage through managed flows in the Wakool River system. Presentation given at the 2011 Annual Australian Society for Fish Biology Conference and 5th Australian Technical Workshop on Fishways. 22 – 24 July 2011, Townsville, North Queensland, Australia.
The Edward-Wakool River system in south-western New South Wales forms the largest anabranch system of the Murray River main channel. The system is a highly braided complex of rivers, creeks and wetlands comprising of approximately 1100 km of water courses. The system has a high ecological value and abundant areas of fish habitat, and historically had diverse fish communities. Progressive regulation since the 1900’s for economic and social development has reduced the dynamics and variability of the flows. The water delivery strategy has lead to prolonged drying resulting in several detrimental problems for the anabranch systems ecology including; drying of refuge pools, fish stranding, high salinity, acidification, vegetative congestion and blackwater events. This has necessitated the delivery of environmental water to help reduce stress on the system. To examine the behaviour of large bodied fish species within the system and their response to water delivery, Murray cod, golden perch, silver perch and common carp were fitted with acoustic tags and an acoustic array of 40 receivers was installed throughout the system. Data collected will assist in the development of watering plans to ensure optimum water delivery to allow fish to access required habitat, utilise migration corridors and return to refuge pools. Early results from the acoustically tagged fish have identified localised and large-scale movements, utilisation of flood runners between main channels, barriers to migration, navigation through barriers, and the use low-flow habitat. Results will be used in the development of a water delivery model for the Wakool river system. This model will be implemented and the acoustic array used to test its suitability.