Lake Cathie fish kill

Dead fish were found in the vicinity of the Perch Hole, one of the estuaries associated with Lake Cathie. Photo: NSW Department of Primary Industries.

Dead fish were found in the vicinity of the Perch Hole, one of the estuaries associated with Lake Cathie. Photo: NSW Department of Primary Industries.

A Lake Cathie property owner has questioned why the lake has not been opened by Port Macquarie-Hastings Council in the wake of fish deaths at Perch Hole.

Council’s website refers to the ‘Opening Strategy’ for Lake Cathie with the decision to manually open the lake usually triggered by the risk of flooding, poor water quality or habitat endangerment.

Robyn Moody has questioned if the habitat endangerment includes dead fish in the water. 

Last week council received a report of dead fish in the vicinity of the Perch Hole, one of the estuaries associated with Lake Cathie. 

Port Macquarie-Hastings Council director Melissa Watkins said council have no plans to open the lake at this stage, however will continue to monitor conditions closely.

Robyn said she believes the lake should be returned to its natural flow and habitat of years gone by. 

The problem,  Robyn said, started when the current bridge crossing the lake and the Kenwood Drive bridge were reconstructed, narrowing the water flow under the bridge.

“The water's natural flow was changed,” she said. 

In 2011 council prepared a hydrodynamic model of the Lake Cathie and Lake Innes systems to test the scenario.

“The results suggest that widening the Kenwood Drive bridge would have had some beneficial impact on water quality between Cathie Creek and Lake Cathie, Ms Watkins said. 

“However the report also found that isolating Lake Innes would provide the greatest impact to tidal flows and water quality.

“The report also found these options would additionally pose the greatest threat to local ecology or other social or economic values through a loss of habitat, increased acidification, fish passage obstruction and destruction of marine vegetation.”

Ms Watkins said it’s unlikely the Lake Cathie and Lake Innes systems can be returned to their natural state, given the urban development that now exists around the lake.

“Council and relevant state government authorities have developed a Lake Opening Strategy that seeks to balance the many economic, social and environmental values the lake system provides to the community,” she said. 

Ms Watkins said Port Macquarie-Hastings Council undertakes water quality monitoring on a monthly basis. 

“Council also took samples last Friday following the reported ‘fish kill’,” Ms Watkins said. 

“These results indicate that water quality indicators (including dissolved oxygen, pH) show the water quality to be generally good.”

Ms Watkins said council and state government authorities have undertaken numerous studies over many years.

“These studies are undertaken by experts in estuary systems and processes,” she said. 

“These professionals consult with locals as required.”

Emergency talks

With the spectre of more dead fish looming over NSW, one state minister has warned against an emergency meeting of stakeholders becoming an ineffective talk-fest.

Up to a million fish are dead in the Darling River at Menindee and more are likely to perish in coming days as temperatures rise.

Despite criticism from scientists and environmental advocates who say mismanagement of water is to blame, the federal and NSW governments are adamant drought is behind the deaths.

Federal Water Minister David Littleproud has asked the Murray-Darling Basin Authority to convene a meeting of water managers and environmental water holders this week.

The federal government wants states to agree to use $5 million from Murray-Darling Basin funds for a strategy to look after native fish.

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