Murray cod (Gugabul, Guduu*) is a protected species under the Environment Protection and Biodiversity Conservation Act 1999. Murray cod have significant cultural value to the First Nations in the Macquarie River valley, and feature in Aboriginal dreaming and are an important food. Murray cod are also an important recreational fishing species.

Populations of Murray cod in the Macquarie River Valley have been impacted by water resource development, loss of habitat and the presence of barriers. Extremely dry conditions led to devastating fish death events in the Macquarie River earlier this year. Importantly last summer, passionate locals and NSW DPI Fisheries rescued and relocated hundreds of native fish including Murray cod to safer waterholes in the Macquarie River.  We now want to ensure we provide conditions for Murray cod to breed and recruit in the Macquarie River Valley.

Water for the environment will support recovery of Murray cod following the drought. Deliveries will be used to provide suitable flows to maintain nests andsupport survival and dispersal of Murray cod. Murray cod breed during spring when water temperatures are above 18oC.  They lay eggs on logs, rocks or under tree rootballs and banks, where the male fish stays to guard the nest. During this time, relatively stable flows are needed to ensure the nest is not disturbed, smothered or exposed.

To get an insight into what our environmental flows will help to happen, take a look at a Murray cod mating, nesting and caring for his eggs.  It is narrated by local fisherman and self confessed Murray cod ‘lover’ Brian Dare and produced by Steve Brooks and Gavin Butler from DPI Fisheries.

 

Environmental flows for Murray cod and his mates…

Rainfall in 2020 has provided a welcome respite from the extreme drought of 2017 to 2019. The Macquarie valley landscape, river flows and water availability have all begun to recover. This spring as temperatures rise, the timing is right to add water for the environment onto rainfall and natural flows to help native fish and wetland vegetation bounce back.

Target Areas: Deliveries will target multiplevlocations, including Murray cod breeding habitat in the mid-Macquarie River, the Macquarie Marshes and the Lower Macquarie River to the Barwon River.

Stable flow: Releases from Burrendong Dam began at the start of October to provide a relatively stable flow in the Macquarie River (~1,000 ML/day at Marebone Weir).

Flow pulse: A flow pulse in late October intoDecember, will see water levels rise to increase theextent and duration of inundation in the Marshes (see Figure 1 below). This allows water-dependent plants enough time to grow and set seed and maintains key waterbird breeding sites.

Deliveries will be managed adaptively to maximise the benefits, minimise disruptive inundation and respond to changing conditions.  We are hopeful that this mix of environmental flows, at different times and quantities will support Murray cod breeding in the Macquarie Valley, along with boosting the overall productivity of the river for other fish, birds and plants.

*Gugabul means Cod in Wiradjuri language. Guduu means Cod in Gomilaroi and Wailwan languages.

Article reproduced from Commonwealth Environmental Water Office Macquarie River Valley 2020–21 Event Update #1

 

Siwan Lovett
Author

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