dead fish
A Queensland estuary groper, estimated to weigh up to 30kg, lies dead on the banks of the Burrum River during the week.

A giant groper has died in the Burrum River, prompting speculation as to why fish are perishing in an apparently healthy waterway.

The stench of decaying fish hangs over sections of the river and stunned barramundi are reportedly being caught by hand as they swim aimlessly in the shallows.

Lifetime local Peter Pearson said he had never seen anything like it in his time living and fishing in the region.

After finding a dead Queensland estuary groper near his Pacific Haven property on Thursday, Mr Pearson said it was time something was done about the problem.

"I would have seen 10 dead barra today," he said.

"And that groper, they are hardy critters, it takes a fair bit to knock one of those around."

After 49 years spent on and around the Burrum, Mr Pearson said the river had always been one of the cleanest in the region.

"We used to test the water monthly, used to send it away for analysis and never found anything wrong with it," he said.

He also dismissed the theory that cold water was responsible for the string of recent fish deaths.

"It's not the water temperature; we've had colder winters than this and fish didn't die, plus there were a lot more barra then.

"I'm worried about it; of course we are worried. We've lived nearby all this time and what's happening is new in our experience."

A spokesperson from the Department of Environment and Resource Management said reports had been made to Wide Bay Water and the Department of Employment, Economic Development and Innovation (DEEDI).

"DERM will continue to liaise with those groups and will conduct an investigation as further information becomes available," the spokesperson said.