There’s something fishy about the amount of water flowing down the Yarra and Watts rivers over the coming weeks … and it’s called the Australian grayling.
Melbourne Water has started releasing millions of litres of water from the Upper Yarra and Maroondah reservoirs with the great flow starting on Thursday, 18 May and expected to continue until 15 June.
Apart from the spectacle such a release creates, the primary purpose of the release is to support juvenile Australian grayling migration and spawning.
Cheryl Edwards, Environmental Water Resources, Melbourne Water said the release was important for the success of the species which spawn in the freshwater reaches of the system before the eggs and larvae drift out to sea.
Macquarie perch also spawn in places where the river flows quickly over a pebble bed, and these locations tend to get clogged with silt during the year.
“The flow from environmental water releases enables the spawning grounds to be cleaned up in preparation for spawning and a steady stream flow allows the eggs to remain stable in the spawning grounds,” Ms Edwards said.
Other species expected to benefit from increased environmental flows include regionally significant river blackfish and the platypus.
River levels can be expected to rise up to 90cm in the Yarra and up to 120cm in the Watts River through Healesville during the release and are within the normal natural variation of these rivers.
In Millgrove, peak flows in the Yarra River will be up to 600 megalitres a day for seven days from 27 May to 4 June.
