Native fish in the Mullaroo Creek and upper Lindsay River are on the move thanks to environmental watering and new environmental infrastructure. In 2015–16, small pulses of water were delivered through these important anabranches at Lindsay, Mulcra and Wallpolla islands, providing ideal conditions for native fish spawning and recruitment.
Watering also partially filled Lake Wallawalla, improving the health of plants on the bed of the lake and supporting waterbird populations.
Recently constructed water-regulating structures on Lindsay River and Mullaroo Creek aim to restore flows and flooding to the Chowilla Floodplains (an icon site in South Australia) and the Lindsay–Wallpolla–Mulcra islands icon site. They also removed barriers to fish movement.
Research by the Arthur Rylah Institute into how native fish use the regulators recorded Murray cod, golden perch, silver perch, bony herring and Australian smelt moving frequently between the different habitats within anabranches and the River Murray. The investigation used telemetry receivers placed along Mullaroo Creek, Potterwalkagee Creek, the Lindsay River and the River Murray.
Lake Wallawalla, by Courtney Johnson
Fish with telemetric trackers swimming past the receivers were able to show how fish navigated through the structures. "Telemetric trackers were attached to 135 fish including Murray cod, golden perch and freshwater catfish," said Mallee Catchment Management Authority (CMA) Chair Sharyon Peart. "These tracking devices showed increased movement of native fish into the creeks over spring and early summer for breeding."
| Site | Volume of water delivered in 2015-16 (ML) |
|---|---|
| Lindsay Island Lake Wallawalla Lindsay River and Mullaroo Creek | 8,000 2,739 |
| Mulcra Island Potterwalkagee Creek | NSW entitlements |
| Walpolla Island Wallpolla East | 600 |
Shared community benefits
Discussions with the Mallee CMA's Aboriginal Reference Group and several on-Country visits have happened across the region to inform Aboriginal stakeholders about environmental watering and to improve the CMA's understanding of Aboriginal aspirations. This will help the CMA to carry out environmental watering that is mutually beneficial.
One golden perch was tracked travelling from Mullaroo Creek to lock 11 near Mildura, an ultramarathon distance of more than 180 km.
Lindsay and Mulcra islands, by Mallee CMA