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Environmental water for the Gwydir's native fish

Commonwealth Environmental Water Office

Media release
28 October 2013

Native fish in the Gwydir Valley will benefit from the release of Commonwealth environmental water to the Mehi River and Carole Creek.

This will be the first action using Commonwealth environmental water to specifically target the Gwydir's in-stream fish habitat in order to stimulate fish breeding and movement.

The Commonwealth Environmental Water Holder, Mr David Papps, said native fish species in the Mehi River and Carole Creek including carp gudgeon, bony bream, spangled perch and rainbowfish are expected to benefit from the flows. The Mehi River also has important populations of freshwater catfish, golden perch and vulnerable Murray cod.

"Environmental water will complement regulated flows to provide an advantage for native fish over invasive species. This targeted local use of environmental water will have long-term benefits for the sustainability of our native fish populations," Mr Papps said.

Mr Papps has approved the use of up to 20 000 megalitres of Commonwealth environmental water in the two waterways, with 15 000 megalitres set aside for the Mehi River and 5000 megalitres for Carole Creek.

The Commonwealth Environmental Water Office has worked closely with the NSW Office of Environment and Heritage, NSW Department of Primary Industries (Fisheries), NSW Office of Water, State Water and scientists from the University of New England to design the flows to achieve maximum benefit for native fish in these streams. They have also engaged with local community groups on planning for use of Commonwealth environmental water in the Gwydir system in 2013-14.

NSW Department of Primary Industries (Fisheries) Manager of Aquatic Habitat Rehabilitation, Cameron Lay, said that the flow regime associated with irrigation deliveries in the Gwydir is generally not, on their own, beneficial for native fish populations due to the timing of irrigation deliveries and the potential for rapid rise and fall of water levels.

"Water temperature, flow duration and habitat availability are all important factors in stimulating native fish to breed and increasing the chances of larval survival. Environmental watering can provide flows at the right time of year that are high enough to inundate suitable habitat for long enough for native fish breeding to be successful," Mr Lay said.

Office of Environment and Heritage Team Leader of Environmental Water for North West Region, Debbie Love, said this was a good example of how several NSW government agencies, scientists and the Commonwealth can work together to provide real environmental benefit at the local scale.

"The water will be delivered as a two day peak of 1,000 megalitres per day in the Mehi and 500 megalitres per day in Carole Creek, in addition to irrigation demand. State Water will then manage the recession for the benefit of fish. The water will have the additional benefits of improving in-stream habitat, increasing food for fish and other aquatic species and stimulating carbon and nutrient cycling throughout the system" Ms Love said.

"These flows are targeted at in-stream habitat and processes and as such will not impact on private property or irrigation water delivery."

The flows, targeting the Mehi River downstream of Combadello Weir and Carole Creek downstream of the off-take, are expected to reach their peak around 28 October 2013. Monitoring of native fish species will be conducted in association with this event. The Commonwealth Environmental Water Office is also keen to receive feedback from the local fishing community about the outcomes from this event.

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