Dept of Climate Change, Energy, Environment & Water
Native Fish Journey: Tracking Flow in Northern Basin
Research in the northern Murray-Darling Basin is improving our understanding of native fish and their response and movements with the benefit of environmental water.
Native fish surveys and monitoring form part of the Commonwealth Environmental Water Holder’s (CEWH) science program, Flow-Monitoring, Evaluation and Research (Flow-MER). This research is crucial for assessing the health of native fish populations following the release of environmental water and provide a ‘baseline’ for future years.
Monitoring in the Macquarie River and Marshes Flow-MER Area discovered that an adventurous golden perch tagged with an acoustic transmitter moved through the northern Marshes, an area that can be a barrier to upstream movement under certain conditions.
The tagged fish was captured and released 70 km downstream at North Willewa Station (near Carinda). It was the first to pass through the northern Marshes since tagging began in 2023.
The fish’s journey north coincided with a pulse of around 1,350 megalitres per day of Commonwealth and NSW water for the environment that went through the northern Marshes. This was the largest amount of water through the area since tracking began.
The research was conducted by Dr Jerom Stocks from the New South Wales Department of Primary Industries and Regional Development (NSW DPIRD) and the team at the University of New South Wales (UNSW) as part of their Flow-MER native fish movement studies.
Continued monitoring will help establish a more robust understanding of the flows that allow native fish to pass through the Marshes and continue upstream.
Positive reports of native fish monitoring also came out of the Lower-Balonne late last year.
Following a couple of unusually wet years from 2021-2023, the Narran Lakes were inundated in March 2024.
The UNSW Centre for Ecosystem Science (CES) Flow-MER fish team seized upon this ideal opportunity to better understand the role Narran Lakes plays in supporting native fish communities in the northern Murray-Darling Basin. The team undertook fish sampling at 11 Narran River and Lake sites.
Led by Dr Dion Iervasi and Jackson Lamin (Austral Research and Consulting) they identified five native fish species: bony bream, spangled perch, golden perch, Hyrtl’s catfish and carp gudgeon. The most abundant was the bony bream, captured at all sites bar one.
Interestingly, no adult Golden perch were caught. Across all nine sites golden perch from 25 to 50 mm long were captured. These fish were less than a year old and likely a product of water flows in early 2024, to support spawning.
Three invasive fish species (goldfish, European carp and eastern gambusia) were also found. A second survey in the region will take place this year, when the water levels in the river are appropriate.
Similar fish-monitoring programs are set to kick-off in autumn in the Darling-Warrego, the Gwydir Areas and the Border, Barwon and Namoi areas of the northern Murray-Darling Basin through Flow-MER.
The autumn fish surveys will be valuable for gauging the health of native fish populations in response to low oxygen events and following summer-autumn environmental flows. This monitoring will be done by NSW DPIRD and Austral Research and Consulting.
https://www.dcceew.gov.au/about/news/where-native-fish-go-when-water-flows-northern-basin