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Work continues to protect Murray Hardyhead

Environmental water will be used to top up the Cardross Drainage Basin as part of ongoing efforts to protect the nationally-threatened Murray Hardyhead.

A total of one gigalitre (GL) of environmental water will be delivered to Cardross Basin 1 East and spill into the adjoining Cardross Basin 1 West, creating the saline conditions Murray Hardyhead need to survive.

The move has been prompted by changes in the water quality in Basin 1 East, which is allowing competition from other species, reducing the Hardyhead chances of survival.  Hardyhead need salinity levels in water to be about 5000 to 6000 EC for an ideal environment with minimal competition from other species. Ongoing drainage into Basin 1 East means the water is currently approximately 1000 EC.

The Mallee Catchment Management Authority (CMA) is co-ordinating the environmental water delivery, on behalf of the Department of Sustainability and Environment (DSE), and in conjunction with Lower Murray Water.

“If salinity is not increased, the population of competing fish will increase and the small wetland habitat may not be able to continue to support the Murray Hardyhead population. This could ultimately lead to the decline of the species at Cardross – a traditional stronghold of the Murray Hardyhead in Victoria,” Mallee CMA chief executive officer Jenny Collins said.

“By allowing Basin 1 East to spill into Basin 1 West, the overall EC level of the basin will increase and effectively double the area of habitat suitable to the Murray Hardyhead ahead of the breeding season later this year.”
The water to be delivered will come from the Victorian River Murray Flora and Fauna Bulk Entitlement, which is water legally set aside to preserve the environment.  It is subject to the same allocations as irrigators and using it does not affect anybody else’s water allocations.

The water will be delivered via existing irrigation infrastructure from mid July.

Efforts to protect the Murray Hardyhead have been underway since 1996, when it became apparent that the future survival of the species was under significant threat. As the Cardross Lakes supported one of only four Murray Hardyhead populations remaining in Victoria at that time, environmental water was delivered to sustain the population.

Initially, the entire basin (East and West) held excess drainage water and environmental water for this purpose, but the area of inundation has decreased over time due to limited water availability. A levee bank was constructed in 2007 to split the basin into two pools (East and West), ensuring environmental water could be delivered to a smaller area to preserve the Murray Hardyhead population.

A five year action plan for the ongoing protection of the Murray Hardyhead in Victoria is being developed by DSE in partnership with the Murray-Darling Freshwater Research Centre and in conjunction with the National Murray Hardyhead Recovery Plan.

Ms Collins said maintaining current populations through environmental watering, establishing captive populations and translocation sites have been necessary actions to prevent the further decline of the species in the short-term.

“We will be keeping a close eye on how this environmental water affects the population of Murray Hardyhead within the Cardross Basin,” Ms Collins said.

“As part of ongoing efforts to save this important fish from extinction, the Murray Darling Freshwater Research Centre will conduct regular monitoring of Cardross Basin 1 East and West, taking into account EC readings and fish numbers.”

For more information on this and other environmental watering projects in the Victorian Mallee, contact the Mallee CMA on 03 5051 4377 or log on to

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