Tasmanian salmon deaths halved in March, indicating mass mortality event is over, EPA says
The Tasmanian salmon industry's mass mortality event is over, the Environment Protection Authority (EPA) says, months after dead fish and fatty globules began washing up on beaches in the state's south.
The state's environment watchdog says
The companies reported 3,395 tonnes of fish waste in March, down from 6,300 in February.
The data showed no salmon went into landfill sites in March, with most of the waste going to land spreading and rendering.
In March, the peak body for
Dead salmon floating in the enclosed fish pens near Southport in February.
(
Supplied: Bob Brown Foundation
)
In a statement on Tuesday, EPA chief executive Catherine Murdoch said conditions were improving.
"Water temperatures are falling and there has been a significant decline in the number of pens above the mortality reporting thresholds in April,"
Ms Murdoch said.
Water quality improves, no antibiotics detected
Water quality in the impacted area has also improved, with independent environmental monitoring of water quality conducted by the EPA no longer
Photo shows
a skip bin with salmon carcasses
With Tasmania's salmon companies reeling from unprecedented losses due to disease and warm weather, the industry is told it will face investigation by the Environment Protection Authority.
"Water quality and beach sediments at four beaches in the southern D'Entrecasteaux Channel found all samples to be below the detection limit for the antibiotic oxytetracycline," the statement read.
"As part of this program, the EPA collected water samples in the last two weeks of March at 10 offshore locations and a significant number of wild fish at four locations within the southern D'Entrecasteaux Channel for analysis and none of these samples detected any antibiotic residues."
The EPA had previously reported February's dead fish waste at about 5,500 tonnes, or roughly 6 per cent of the industry's annual production.
The dead fish came from pens in the D'Entrecasteaux Channel, in south-eastern Tasmania, owned by Huon Aquaculture and Tassal.
Mandated industry reporting on salmon mortalities began earlier this year, with the EPA saying they intend to publish data quarterly going forward.
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Ms Coughanowr said a marine event of the scale of South Australia's toxic algal bloom, which is bringing unprecedented destruction to the state's marine environment, "would be a terrible outcome for Tasmania". "It is important that we don't just blunder into this with our eyes closed," she said. A spokesperson for NRE Tasmania said Biosecurity Tasmania was continuing to look into the recent deaths of the sardines found along the shores of the River Derwent. "At this stage, investigations indicate this mortality event is not linked to the salmon mortality incident in south-east Tasmania from January to April," the spokesperson said. "Biosecurity Tasmania understands it is not pollution-related and the events are likely due to different infectious causes. From ongoing testing, and POMV have been ruled out as the cause of the sardine deaths. "Initial results of testing conducted of the sardines indicate it is likely to be a result of Heterosigma, a type of algae. It is currently not believed to be a bloom, however further testing continues." Ms Coughanowr said whatever the cause of the most recent fish deaths, the health of our waterways needed to be a priority for Tasmania. "We need to reduce pollution and other pressures on our rivers and coastal waters to make them as resilient as possible," she said. Members of the public who observe dead fish, pollution events or suspected biological material can call the Emergency Animal Disease Hotline on 1800 675 888 or the EPA Incident Response Hotline on 1800 005 171.
