An estimated 10,000 were killed just weeks ago, and locals fear native stocks could be all but wiped out this time

This article is more than 1 year old

This article is more than 1 year old

Hundreds of thousands of fish have been killed along a stretch of the Lower Darling River in New South Wales in a second major incident which has led some experts to fear whole populations of local native fish have been wiped out.

Residents near the Menindee Lakes are reporting what is the second major fish kill along a 20km stretch of water near Weir 32.

An incident before Christmas saw an estimated 10,000 fish die.

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Locals have been posting photos of dying fish washed up along the shores of the lakes which are about 100km east of Broken Hill.

And local fish experts are saying that it could all but wipe out the populations of Murray cod and other native fish, raising serious questions about the way WaterNSW is managing the lakes system.

Facebook Twitter Pinterest Photos posted on social media of the fish kill at Menindee on the Darling River. Photograph: Graeme McCrabb/Facebook

Two years ago the lakes were almost full. But WaterNSW has been releasing water and allowing extraction upstream for irrigation at a rate that has left the lakes almost completely dry.

According to the WaterNSW website, there is just 2.5% of water remaining in the lakes.

Rod McKenzie, a fishing journalist and angler, who runs tours of the Murray-Darling, said he feared the kill would spell the end of a once great fishery.

“It’s an absolute tragedy. This is a world-scale fish kill, but the catastrophe has been so well orchestrated and there is so much money involved you won’t get to the bottom of it,” he said.

“If it were native animals like koalas and platypuses and they were lying by the side of the road, people would be up in arms,” he said.

Just before Christmas about 10,000 fish were estimated to have died in mass death incident in a 40km stretch a little further upstream.

Investigations by the Department of Primary Industries confirmed that Murray cod, golden and silver perch and bony bream had died in that event.

DPI said it had visited the Menindee Lakes on Monday and “confirmed had been a major fish kill event in the Darling river at Menindee affecting hundreds of thousands of fish, including golden perch, Murray cod, and Bony Herring”.

DPI senior fisheries manager, Anthony Townsend, said the department would use the incident to learn more about our native fish and improve management.

He said the incident seemed to have resulted from a sudden drop in temperature which may have disrupted an existing algal bloom, killing it and leading to a depletion of dissolved oxygen in the river water. This would have exacerbated poor water quality for already stressed fish.

At the time of the first incident WaterNSW and the NSW Department of Primary Industry blamed the drought.

“The ongoing drought conditions across western New South Wales have resulted in fish kills,” they said in a joint statement.

The DPI’s director of aquatic environment, Sarah Fairfull, said the prolonged dry period resulted in poor water quality along much of the Darling River and in other valleys.

WaterNSW said at the time it was continuing to monitor water quality throughout the dams and river systems.

The latest incident will again raise questions about the NSW government’s stewardship of the Murray-Darling River system, which has been under intense scrutiny since the ABC Four Corners program aired allegations of water theft by irrigators and a close relationship between senior bureaucrats and major water users.

Since the 1960s, the original Menindee Lakes have been significantly altered to serve as a major storage for water for the Murray-Darling Basin as well as the water supply for Broken Hill. The lakes are also a major fish breeding area for native fish, and critical to maintaining stocks of fish throughout the river system.

However, the NSW government has proposed shrinking the lakes and altering the way it manages the water storage, in order to reduce evaporation. It is currently building a $500m pipeline from the Murray to Broken Hill in order to provide the inland city with an alternative water supply.

But the plan is highly controversial because it will mean the government has less reason to keep the lakes full and will likely see the Lower Darling run dry more often.

Local graziers and the towns of Wilcannia and Pooncarie are up in arms about the state of the river, accusing the NSW government of sacrificing their 500km stretch of the Darling in order to benefit upstream cotton growers.

They say the current crisis is due to Water NSW’s decision to run the lakes dry despite forecasts of drought.

Local grazier Julie McClure said there was virtually no water flowing under the bridge at Tilpa where she lives.

“One neighbour is drawing water for stock and homestead use from a green stagnant pool. When she showers, she takes a bucket of rainwater to rinse off after using the river water,” she said.

“It smells like a fish market. There should be some rules around emergency water management.”

The new plan for Menindee Lakes is currently before the Murray Darling Basin Authority as part of a suite of projects that the states are proposing as an alternative to buying water for the environment from farmers. The idea is that the projects will deliver equivalent environmental outcomes. The Menindee Lakes project has received a very poor assessment by the authority’s experts.

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Centre Alliance senator Rex Patrick said: “The Darling River is going into cardiac arrest and both the federal and NSW governments are asleep at the wheel of the ambulance.”

He called on the federal government to step in and ensure that water from recent rain in Queensland was used to deal with the environmental emergency occurring in northern NSW and the Lower Darling.

“With less than 250ML per day flowing over Weir 32 there must be no water flowing from the Darling River into the Murray. The Darling River, a river that is crucial for river flow through the Murray mouth and into the Coorong, is dying and the government is simply not acting.”

“The government cannot ignore what is going on. The river is stagnant, the government can’t be”.