06 July 2018
Council will continue to monitor a fish kill at Clarrie Hall Dam over the weekend and remove dead fish as required.
Today about 500 Australian bass were found dead in the deepest part of the dam, near the spillway. These fish have now been removed and disposed of appropriately.
“Clarrie Hall Dam has undergone a seasonal overturn in the past two weeks, where the deeper
de-oxygenated waters have upwelled to the top of the water column,” Acting Manager Water and Wastewater Michael Wraight said.
“This is a natural process and happens annually around the beginning of winter as the top water layers cool and sink to the bottom forcing the bottom layers up.”
Historically there have been overturn events at Clarrie Hall Dam, which have resulted in similar fish deaths.
Testing of water samples in the dam over the past two weeks shows very low oxygen levels in all levels of the dam near the spillway.
“It is likely that these low dissolved oxygen levels have resulted in the death of the fish. We don’t expect it to get any worse but will continue to monitor the situation,” Mr Wraight said.
New South Wales Fisheries has been advised of the fish kill.
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