DURING late summer and early autumn, the people who operate the Murray and Goulburn rivers had fish on their mind as they carefully delivered water to meet the demands of irrigators and the environment.
The native fish population get going when the movement of water in the rivers is well coordinated – it stimulates the young ones to move from the Murray River into upstream tributaries, where they tend to stay and grow.
“There’s more to it than just delivering water from one point in the system to the next,” said Murray-Darling Basin Authority (MDBA) head of Environmental Management, Carl Binning.
“It’s an example of sophisticated river management under the Basin Plan, where operators in different valleys coordinate their efforts to get results for the ecosystems right along the river system, as well as benefiting irrigators who have ordered water.
“At this time of year, young fish in the Murray can pick up signals from boosted flows that are entering the river from tributaries such as the Goulburn. They respond by moving up river into smaller streams where there is food and shelter.
“Surveys of similar flows in the Goulburn and Campaspe rivers this time last year found that around 70% of these fish remained in the tributaries, and catches of silver perch in the Goulburn and Campaspe Rivers increased in the months that followed – good news for recreational fishers.”
Silver perch and golden perch have been tagged with radio transmitters by scientists at the Arthur Rylah Institute for Environmental Research, as part of MDBA and Victorian Government funded monitoring projects. Researchers will monitor native fish responses to the current flows in the coming months.
Enabling greater fish movement in the Goulburn River has been a joint effort between the MDBA, Commonwealth Environmental Water Holder, the Victorian Environmental Water Holder, Goulburn Broken Catchment Management Authority and Goulburn–Murray Water.
“Together with our state and commonwealth partners, the MDBA works out which part of the environment is in greatest need of water over the year or two ahead and what actions are most needed. This helps to sustain species such as golden perch and silver perch in the long term,” Mr Binning said.
“We’re putting into action the most recent scientific understanding, which includes knowledge of interconnecting flows that help golden perch and silver perch to thrive.”