Almost A Million Fish Have Washed Up Dead In NSW Drought

Hundreds of thousands of fish have washed up dead along a stretch of the Lower Darling River in NSW for a second time in weeks.

Locals have posted eye-opening photos and videos of the carnage washing up on the shores of the Menindee Lakes in far western NSW.

Rob Gregory posted footage of hundreds of dead fish to Facebook. Source: Facebook.

Dry conditions and a sudden temperature drop is believed to have disrupted an existing algal bloom, killing the algae and depleting dissolved oxygen, resulting in poor water quality which stresses the fish, DPI Senior Fisheries Manager, Anthony Townsend said.

With more hot and dry weather on the way and just 2.5 percent of water remaining in the lakes, we're being warned to expect more mass deaths.

“The current low flows and warming temperatures are likely to pose an ongoing threat to native fish throughout the summer," Townsend said.

WaterNSW executive manager Adrian Langdon told AAP it was "almost certain" the worsening water quality will continue and possibly increase as the hot weather persists without significant rainfall.

Some experts fear the events could all but wipe out populations of Murray cod and other native fish.

IMAGE: Facebook/Menindee RegionCommunityGroupOnTheDarlingRiver

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The NSW government and Water NSW are investigating the events.

"All of this new knowledge will help improve how we manage waterways and the fishery across the entire Murray-Darling Basin to help protect and improve native fish populations when conditions improve," Townsend said.

'Muzza', Sydney Aquarium's resident one-metre long Murray Cod fish IMAGE: Greg Wood/Getty

Thankfully it's not all doom and gloom for our underwater population.

Thousands of fish trapped in a pond near Wellington in the central western NSW have been rescued. 

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The Murray cod, golden perch, and catfish were among the species stranded in the dissipator pond below Burrendong Dam after flood waters receded in 2016.

Water and oxygen have been pumped into the pond for two years to keep the fish alive.

The pond has now been drained, with the fish netted and released in the Macquarie River.