Water for the environment has been delivered into the Macquarie River Wambuul in central NSW as part of a managed release to help native fish reach winter refuges.
New South Wales Department of Planning and Environment Senior Wetlands and Rivers Conservation Officer Tim Hosking said water for the environment was added to create a pulse to assist native fish migration to winter refuge areas.
“The Lower Macquarie River below the Marshes and the Macquarie Marshes themselves are not a particularly good drought refuge for native fish, as flows recede through winter. This environmental flow is designed to encourage and allow native fish to move upstream into the mid-Macquarie River where there is a permanent supply of water from Burrendong Dam,” Mr Hosking said.
Commonwealth Environmental Water Holder Dr Simon Banks said the joint watering action with NSW was an ideal way to help native fish move ahead of what is anticipated to be dry times.
“Native fish need to build condition in the cooler months in preparation for breeding – we have a window of opportunity now and we’re keen to use it,” Dr Banks said.
“My office has provided funding to NSW DPI Fisheries for a monitoring project in the Macquarie River to assess golden perch movement and population sources.
“Up to 35 fish tracking receivers have been deployed at key river junctions and instream barriers along the Macquarie River from Warren to the Barwon River, and up to 100 juvenile perch tagged with acoustic transmitters. This monitoring will help us understand the success of the addition of water for the environment as well as pave the way for future similar actions,” he said.
Mr Hosking emphasised that consecutive wet years have seen great connectivity across the Murray Darling Basin, with native fish spawning and movement into the Macquarie catchment from the Barwon downstream.
However, with the Bureau of Meteorology predicting drying conditions in 2023, Mr Hosking said concerns about fish becoming stranded have increased.
“We know there are native fish throughout the lower river after the strong connectivity to the Barwon River during the past couple of years, particularly golden perch (gagalin). We want to protect the native fish in the catchment and allow them to move to safer locations,” Mr Hosking said.
Macquarie Cudgegong Environmental Water Advisory Group (EWAG) Chairperson Ian Rogan said it is one of the first times an autumn environmental flow event has been attempted.
This event, Mr Rogan said, is an example of adaptive water management - targeting specific ecological outcomes while considering seasonal conditions and the latest information on the life cycles of native fish, like golden perch.
While the catchment is famous for its iconic Macquarie Marshes and waterbird population, this environmental water event is indicative of a broader focus for the EWAG.
“Targeted flows while we have favourable environmental conditions can help native fish recruitment and spread the population in the catchment,” Mr Rogan said.
The event is a partnership between the NSW Government’s Water for the Environment program and the Commonwealth Environment Water Holder.
