IN a bid to help heat stressed native fish in the western Riverina’s Niemur River, additional water is now flowing from the Edward River into the Niemur via Stevens Weir and Colligen Creek.
The Niemur River has populations of Murray cod, golden perch, bony bream, and other native species.
Paul Childs from the NSW Office of Environment and Heritage said improving oxygen levels and stabilising water temperatures was challenging, especially during hot, dry weather.
“Native fish habitat in the Niemur River has been under heat stress this summer with repeated 40 degree days in the area.
“At times the water temperature has risen suddenly from about 25 degrees to 30 degrees, which threatens the survival of native fish including bony bream.
“When the Niemur River is healthy, the dissolved oxygen is above 6 milligrams per litre, but in January it was 4.2. Native fish become stressed at this level and a further drop of two points would have been critically dangerous.”
The Commonwealth Environmental Water Holder, David Papps, approved the use of this water. Mr Papps said this flow down the Niemur River had support from the local community and NSW state government agencies.
“This use of Commonwealth environmental water in the Niemur River is a great example of the collaborative effort in place locally, to identify and respond to changing water quality conditions that could potentially impact on native fish like Murray cod,” Mr Papps said.
“It also builds on the past use of environmental water in the Edward-Wakool and other catchments in the Murray-Darling Basin to assist with maintaining and improving conditions for native fish.”
The Office of Environment and Heritage empowers communities to get directly involved in caring for local environments. Mr Childs said water was being delivered down the Niemur River at a rate of 200 megalitres per day throughout February and early March.
“Dissolved oxygen is monitored and when the levels fell below safety thresholds stakeholders agreed that an environmental flow was the most appropriate action to improve water quality,” Mr Childs said.
The agreement was reached by the Murray and Districts Dissolved Oxygen Group which is coordinated by Murray Local Land Services and is made up a range of stakeholders including OEH, State Water Corporation, NSW Office of Water, Commonwealth Environmental Water Office, NSW DPI (Fisheries), researchers (Charles Sturt University and Murray-Darling Freshwater Research Centre) and members of the community.
Read more about managing the Murray River Catchment: http://www.environment.nsw.gov.au/ieo/murray/maptext-04.htm
