DPI called in to investigate hundreds of dead fish found in Chaffey Dam, near Nundle

The state government has launched an investigation to find out what is killing the native species in the dam, near Nundle. 

Identified as mostly silver and golden perch, the fish have begun to rot among the debris at the southern tip of the dam, just up from Bowling Alley Point, near the Nundle Rd bridge.

It was originally feared the fertiliser of nearby farms may have washed into the water, causing its nitrogen levels to spike.

However, experts believe a naturally-occurring event could be the cause.

A large amount of organic matter has been washed into the waterway in recent weeks by heavy downpours and strong inflows and as it begins to break down, reduces oxygen levels in the water.

A Department of Primary Industries (DPI) spokesman said it was notified more than a week ago by concerned locals, when more than a hundred fish were found floating in the water.

“Fisheries officers have investigated a report from a member of the public which resulted in a large number of silver perch found dead and decomposing along the foreshores of Chaffey Dam, near Tamworth,” the spokesman said. 

“Officers believe the fish kill is a result of the large amount of organic matter and debris that has washed into the dam after recent rain events, causing de-oxygenation of the water as it breaks down.”

Nundle resident Rory O'Callaghan noticed the fish on Friday morning and was stunned by what he saw, he told The Leader.

“I went down there to have a look at how much water was in the dam,” Mr O’Callaghan said.

“There was easily more than 50 on one side of the bank, just up from the flood monument.

“It was strange seeing so many dead.”

A keen angler, Mr O'Callaghan said he fished all along the river to the dam, but it could be difficult to get a bite in Chaffey.

“I was stunned there were some decent size fish,” he said.

“The first fish I noticed was a silver perch, which was at least 70 centimetres long. It was a shame to see such a big fish belly up.”

While the native silver perch and yellowbelly have been affected, plenty of carp were seem swimming through the debris-laden water.

DPI Fisheries officers returned to the site on Tuesday to conduct more water testing and noted the conditions had improved. “Officers did not observe any dead or dying fish and predict conditions are returning to normal,” the spokesman said.