Tasmanian salmon producer Huon Aquaculture has revealed it used antibiotics to treat diseased fish at its freshwater hatchery, sparking calls for mandatory disclosure rules.
The company administered oxytetracycline to salmon at its Meadowbank facility on the River Derwent after warm water temperatures in mid-January triggered an intestinal bacterial infection.
Huon’s general manager of aquaculture Depha Miedecke said the medication was given to two groups of fish over 20 days under veterinary advice.
“Things got quite warm and subsequently we saw an increase in mortality,” she told ABC Radio.
“This was caused by intestinal bacterial infection that can sometimes affect salmon and other fish.”
The company voluntarily reported the treatment to the Environment Protection Authority (EPA), as there is currently no legal requirement to disclose antibiotic use in freshwater hatcheries.
The EPA has since introduced antibiotic residue monitoring at the site and plans to extend the requirements to all freshwater hatcheries statewide.
Independent MLC Meg Webb criticised what she called a “murky lack of transparency” in the industry.
“We need to have people who are experts looking at this, we need the community to know that full information is being provided and assessed,” she said.
The Meadowbank hatchery sits within Hobart’s water catchment area, about 40 kilometres upstream from TasWater’s Bryn Estyn treatment plant.
Downstream users were not notified of the antibiotic use.
Stricter rules already apply to the antibiotic florfenicol in coastal marine farms, with salmon companies required to publish real-time updates showing when and where the drug is used.
The Greens have called on the government to mandate similar disclosures for all antibiotic use in Tasmanian waters.
“Tasmanians deserve transparency about what is happening in the waterways that could affect human and environmental health,” Greens MP Tabatha Badger said.
“Tasmanians are rightly questioning why this antibiotic use wasn’t reported in real-time, like when florfenicol is used in marine waters.”
Health Minister Bridget Archer said she had no public health concerns, describing antibiotic use in the industry as “heavily regulated”.
