Dead fish found near Menindee spark fears of another mass kill

Dead Murray cod have been found downstream of Menindee, amid fears of another major fish kill at the Menindee Lakes. We ask an expert for their opinion.

Suffocated Murray cod found downstream of Menindee. Picture: Ty Helms

MORE than 20 dead Murray cod have been found downstream of Menindee, sparking fears of a repeat of a mass fish kill nearby where more than one million native fish perished last summer.

Menindee resident Ty Helms found the fish in a watering hole near the Menindee Lakes, NSW, on Friday.

Graeme McCrabb, who holds a permit to relocate stressed Murray cod in pools near Menindee, estimated the number of fish deaths over the past six months between 500 and 1000 in the 500km stretch to the Murray River, and predicted another mass kill next year.

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“As the summer rolls on and water quality decreases, it’s just a matter of when,” Mr McCrabb said.

The recent fish deaths have sparked fears of another large fish kill less than a year after three between December last year and January this year on the same 45km stretch of the Darling River between Menindee Main Weir and Weir 32 in the Lower Darling.

The NSW Department of Primary Industries was assessing the incident on Friday.

A spokeswoman said fisheries staff were preparing for further fish deaths in the Darling River and its tributaries this summer.

A Federal Government-appointment independent panel said in its final report on the 2018-19 fish deaths there were three main immediate causes;: low flows, poor water quality and a sudden change in temperature.

Broken Hill is expected to reach 43C today with a shower and a gusty thunderstorm forecast in the afternoon or evening. The temperature is set to drop by more than 10C by tomorrow to a top of 31.

But Professor Robert Vertessy, who chaired the independent panel assessing the fish deaths, said the weather forecast for today and tomorrow was unlikely to be as extreme as it was at the same time last year, which preceded the first mass fish kill.

On December 12 last year the temperature dropped from 39C to 24C in a day, and then to 19C on the following day.

“Really you need a significant and persistent drop to cool the water down to trigger the turnover (stratification, which robs the fish of oxygen),” Prof Vertessy said.

“I have no doubt the conditions there are very serious at the moment. Whether that weather change will trigger something is a bit unclear and the outcome is completely contingent on the number of fish in those weir pools.”