movement and Goulburn/ Determining how flows spawning of nest support stocked fish Broken building native fish populations in terms of movement and survival has some merit. 6. Can environmental Summer/autumn Intervention Loddon/ Golden perch Hydraulics Synchronising Catchment CMAs In most summers, large flows be used to (Jan/Feb) fresh of flows with numbers of 1-year old Pyramid Silver perch Migration & FV increase populations of 10+ days duration to Murray River golden perch and silver Regional Campaspe Age structure MDBA target species in rise at least 0.3 m perch migrate from Victorian Tributaries of above downstream nursery ‘normal’ Goulburn/ CPUE? the Murray through the summer level. Must habitats upstream along Broken Distribution use of attraction flows be integrated with the Murray adjacent to (summer /autumn Murray River rise the Vic/NSW tributaries. Gunbower juvenile emigration (e.g. >8,000 ML/d at These fish then appear to flows or spring adult Torrumbarry) disperse into the upper flows)? Murray and NSW/Vic tributaries. Synchronising a small summer rise in Vic. tribs with this summer fish migration may attract fish into Vic tribs and contribute to demonstrable Initial has already been demonstrated in the Gunbower and Pyramid systems. 7. Does environmental Late winter/early Intervention Loddon Murray cod Hydraulics Catchment CMAs Murray cod can spawn flow management used spring rise to & independently of a river Campaspe Trout cod Larvae for Murray cod and bankfull and Regional rise but in some irrigation Goulburn/ Freshwater YOY other native species hold for up to 21 systems the fluctuation in catfish result in higher days river height due to Broken Age structure survival? irrigation demand is too Mullaroo CPUE far outside that of natural and negatively impacts Productivity life-history processes Growth (e.g. spawning). Environmental water to fill in the in the flow ‘gaps’ regime to reduce overt
movement and spawning of nest building native fish Goulburn/ Broken Determining how flows support stocked fish populations in terms of movement and survival has some merit. 6. Can environmental flows be used to increase populations of target species in Victorian Tributaries of the Murray through the use of attraction flows (summer /autumn juvenile emigration flows or spring adult flows)? Summer/autumn (Jan/Feb) fresh of 10+ days duration to rise at least 0.3 m above ‘normal’ summer level. Must be integrated with Murray River rise (e.g. >8,000 ML/d at Torrumbarry) Intervention Loddon/ Pyramid Campaspe Goulburn/ Broken Gunbower Golden perch Silver perch Hydraulics Migration Age structure CPUE? Distribution Synchronising flows with Murray River Catchment & Regional CMAs FV MDBA In most summers, large numbers of 1-year old golden perch and silver perch migrate from downstream nursery habitats upstream along the Murray adjacent to the Vic/NSW tributaries. These fish then appear to disperse into the upper Murray and NSW/Vic tributaries. Synchronising a small summer rise in Vic. tribs with this summer fish migration may attract fish into Vic tribs and contribute to demonstrable Initial has already been demonstrated in the Gunbower and Pyramid systems. 7. Does environmental flow management used for Murray cod and other native species result in higher survival? Late winter/early spring rise to bankfull and hold for up to 21 days Intervention Loddon Campaspe Goulburn/ Broken Mullaroo Murray cod Trout cod Freshwater catfish Hydraulics Larvae YOY Age structure CPUE Productivity Growth Catchment & Regional CMAs Murray cod can spawn independently of a river rise but in some irrigation systems the fluctuation in river height due to irrigation demand is too far outside that of natural and negatively impacts life-history processes (e.g. spawning). Environmental water to fill in the ‘gaps’ in the flow regime to reduce overt