Scientists to Monitor Fish Flow Benefits

Up to 250,000 megalitres of environmental water is being utilised from both Commonwealth and NSW accounts to help stimulate the breeding of Murray cod over 40 days, said DPI Executive Director Fisheries NSW, Dr Geoff Allan.

The flow will remain well below full bank level, being delivered at a rate of about 6000 megalitres a day to maintain river levels down stream of Gogeldrie Weir for approximately one month.

The flows are intended to support cod spawning and the dispersal of juveniles throughout the Murrumbidgee system.

This is potentially an enormous step forward for the populations of Murray Cod within the Murrumbidgee.

Dr Allan said fisheries scientists and managers had worked closely with water management agencies to develop an environmental release aimed specifically at Murray cod within the Murrumbidgee.

The combined measures of protection of the cod spawning season through fishing closures until 1 December and the allocation of environmental water to support their nesting will optimise survival of the next generation.

Dr Lee Baumgartner, a Senior Fisheries Research Scientist said the flow will maintain a stable water level to protect nests prepared by male Murray cod in readiness for the females to lay their eggs.

Male fish need time to establish nests and then attract females, said Dr Baumgartner.

Once eggs are deposited, they take about 8-9 days to hatch and the larvae are then guarded by the male for another seven days.

It is important the nest is protected during that time because any disturbance can cause fish to abandon their eggs or young.

Dr Allan said plans were underway to monitor the level of benefit the water provides to the Murray cod.

Fisheries researchers will be closely monitoring the outcome of the environmental flow to ensure the water release is achieving the anticipated benefits for the cod population and aquatic health in the Murrumbidgee as a whole.