South Australian irrigators are concerned a noxious fish will become a major issue when watering crops as farmers upstream battle with blocked filters and pipes from the pest species.
It comes after growers have dealt with months of poor water quality and power supply issues in SA's Riverland and Victoria's Sunraysia regions, as a result of the Murray River flood event.
The fish, known as the oriental weatherloach, is a class one noxious species and when caught or captured cannot be returned to the water, due to the threat it poses to native species and the ecosystem.
As it continues to wreak havoc upstream, it has also been detected in the upper reaches of SA's leg of the Murray River.
That has prompted Renmark wine grape grower Joe Catalano to warn other irrigators of the potential risks.
He was investigating a problem with an irrigation filter on his 16-hectare property when he discovered an oriental weatherloach inside.
"I'd never heard of them before," he said.
"You don't want an invasive species full stop, and anything that is going to affect the filtration of water is a concern.
"There's another gentleman a couple of kilometres from me who has been getting quite a few through his filters."
Fish number concerns
The Renmark Irrigation Trust (RIT) said it was concerned about the fish with reports coming in from its members locally, and was seeking advice from irrigation bodies upstream on how to deal with the pest.
"It is getting into their systems, pipe networks and filters, it is really causing havoc upstream and we have just started to notice it ourselves," RIT chief executive Rosalie Auricht said.
"It's a bit like a locust plague but in the water. We hope this won't be an ongoing problem."
Fisheries New South Wales senior manager Ian Ellis said while the fish was a relatively new pest, its numbers had gone "berserk" since the flood, causing serious damage.
"I've seen photos of pump filters which have just been clogged full of weatherloaches, dozens and dozens of them ... pushing through the hoses and pipes," he said.
"We haven't seen this before, so we don't know what will happen but we expect numbers to fall after the flood subsides."
Mr Ellis said more direct measures were needed to dispose of them.
"If you catch some, get them in your yabby traps, the best way to humanely kill them is with a blow to the back of the head or put them in ice to put them to sleep and then bury them," he said.
"Make sure they're well and truly dead. There's no point just chucking them onto the bank as they can get across land and they'll make their way back to the water."
