Eyewitnesses have spotted dead fish on the surface of irrigation channels on Gibsons Road in Sale after Southern Rural Water (SRW) recently completed its annual weed control program of channels in the Macalister Irrigation District.
SRW said the weed control takes place in spring and early summer, when weeds are at their most vigorous, and is done to ensure the irrigation channels are operating at maximum capacity.
The Environmental Protection Authority (EPA) said in a pollution report that the annual weed control program involves the “injection of herbicide into irrigation channels to kill submerged vegetation that restricts water flow”. This occurred on Monday, December 5 in the channel on Gibsons Rd where the dead fish were found by multiple people.
One witness said they first observed the dead fish and other animals on the surface last Thursday (December 8), with other observers taking photos. The witness said they also saw dead frogs and turtles, and believed most of the dead animals may have sunk to the bottom. This individual provided photos, expressing their concern about the environment.
Another witness, who has for years walked their dogs along the channel, told the Gippsland Times that last week they just saw all these “belly-up fish”.
“It was on Gibsons Rd, between Bengworden and Cobain Rds, almost smack down the middle,” they said.
“I thought maybe someone was fishing there … I saw half a dozen, maybe 10 (fish) carcasses on the trail.
“No smell or anything. I wouldn’t have even noticed if not for the dead fish on the trail
“My dogs are not eating them, thankfully. They sniff it and walk away.”
The witness said they had not seen anything like it in 10 years.
“Some of the (fish) were on the grass. I guess if the water is not good, they’ll thrash and jump out,” they said.
“Generally it’s a pleasant place to walk.”
SRW manager environment and climate adaptation, Kate Berg, told the Gippsland Times that an investigation of the channels found European carp.
“The purpose of irrigation channels is to deliver irrigation water to Southern Rural Water customers, who produce food and fibre,” Ms Berg said.
“They are not natural waterways, or intended for use as habitat for aquatic life.
“Our investigations found that European carp, a noxious invasive fish species, were in the channels, and these have been removed and sent to an authorised waste facility in Bairnsdale. No other animals were found by us.
“The Environment Protection Authority has been notified, and decided not to inspect the irrigation channels because our monitoring data shows that there was unlikely to be any impact to natural waterways.
“When we undertake weed control treatment, we notify affected customers directly, and we undertake advertising in local media to notify the community.”
A pollution report from the EPA, seen by the Gippsland Times, goes into more detail about the herbicide used and how it affects structures like the channel on Gibsons Rd.
“The herbicide is approved for channel maintenance, and many water authorities in Australia use it for this purpose,” it reads.
“It breaks down within two-to-three days and works by removing oxygen from the water, which inadvertently causes the death of any fish or other gilled animals that may have entered the channel. The channel is an artificial structure managed solely for distribution of irrigation water and is not intended to provide habitat for aquatic wildlife.
“EPA has reviewed Southern Rural Water’s operating procedures and monitoring program, and is satisfied that it has appropriate controls in place to prevent the herbicide from leaving the channels and impacting upon any natural waterways, including the ocean.”
