A tiny species of fish once caught by the bucketful in Queensland's upper Condamine River is on the verge of extinction.
Scientists are worried the northern river blackfish – more commonly known as the nicky fish or the nicky long cod – could be the signalling an environmental collapse in the Murray-Darling Basin river system.
The species, already highly vulnerable to localised extinctions, is in severe decline.
Over the next two years Southern Queensland Landscapes will try to reduce sediment and increase natural habitat in the streams where the fish still live, including in Killarney, at the headwaters of the Condamine River in Southern Queensland.
Griffith University research fellow Mishca Turshwell hopes more people learn about the species as the effort to save it ramps up.
"They're an interesting little critter and, I think, definitely under-appreciated and undervalued," he said.
Sweet and plentiful
No-one really knows how many are left, but scientists at Southern Queensland Landscapes are convinced the species is in serious decline because of habitat destruction and diminishing water quality.
Killarney resident Bernice Petersen, a centenarian, remembers her grandmother catching the northern river blackfish in vast numbers.
"Lots of times she would get 20 or so in a day," she said.
"My grandmother used to walk from Killarney up to the kiosk to fish, but she caught a lot of nickys and crawfish and we used to dangle our lines alongside hers because she was catching them all.
"They used to share them around if they got too many, the fish was sweet to eat.
An unhealthy system
The creek system is no longer suitable for swimming near Killarney because of the amount of silt in the water, according to Mrs Petersen's son, Neil.
"There was a waterfall when I was a kid and I remember going there once for a picnic and there were adults getting the fish," he said.
"I could see them coming down over the waterfall.
"There were good swimming pools up there when we were kids, but you couldn't swim in it now — it's so filled up with silt and everything."
Aboriginal elder Sam Bonner said his people used to drink from the streams near Killarney decades ago.
"They haven't looked after the water, but how could they when they cut down all the trees?" he said.
"The water is muddy and hot."
'Canary in the coal mine'
Dr Turschwell is not sure if the fish can be saved.
"The black fish have sort of been described as a canary in the coal mine," he said.
"They are a non-migratory species, so they're a good indicator, because they don't have that ability to move around and potentially find better habitat.
Dr Turschwell says the upper Condamine headwaters are critical for maintaining blackfish presence in Queensland, if not the wider basin.
