2 days ago
Tasmania looks to fast-track new antibiotic for farmed salmon as bacterial disease continues to spread
The Tasmanian government is seeking fast-tracked approval for another antibiotic to be used to treat farmed salmon in public waterways as it continues to grapple with an endemic bacterial disease.
Piscirickettsia salmonis — or P. salmonis — is continuing to circulate in salmon pens in southern Tasmania after a mass mortality event in the summer, with fears over warmer winter and spring conditions.
Crossbench MPs were briefed on Friday, and claim that the urgency was due to a worsening outbreak in at least one part of the D'Entrecasteaux Channel, which they say was confirmed under questioning during the briefing.
The government has avoided using the term "outbreak", instead describing the disease as "endemic" in multiple regions and that mortalities have not reached reportable levels at this stage.
Farmed salmon were treated with an oxytetracycline antibiotic during the summer outbreak, when globules of fat from dead fish washed up on multiple beaches.
The industry is now pushing for the use of an antibiotic called Florfenicol — which would require new approvals — and has been engaging with the government since February.
Primary Industries Minister Gavin Pearce said oxytetracycline had "limited uses" and that he wanted to push ahead with Florfenicol.
"This is not listed on Australian labels and approved, however, that process is going forward with the authority at the moment," Mr Pearce said.
"We're looking at probably four to six weeks by the time we get an interim permit for that use.
Tasmania's Natural Resources and Environment Department confirmed that compliance and intelligence gathering was occurring over farmed fish pens in southern Tasmania, to monitor any increased mortalities.
Acting chief veterinary officer Deborah McSweyn said the new antibiotic would be administered as a top coat feed, which could spread into the surrounding marine environment.
"There is absolutely every chance that it will spread beyond the pens," she said.
"That is why we collaborate with the EPA [Environmental Protection Authority] to do really robust and very rigorous testing to monitor those effects."
The EPA is developing a monitoring schedule for Florfenicol to determine how it spreads into the marine environment once administered for farmed fish.
The EPA publishes monitoring reports online, but does not disclose when antibiotic use begins, leaving it up to salmon companies to disclose.
The extent of current fish mortalities has not been publicly released.
Under Tasmanian regulations, mortality events are only reported if more than 0.25 per cent of fish die in a pen over three consecutive days.
Independent Franklin MP Peter George told ABC Radio Hobart that Premier Jeremy Rockliff contacted him on Thursday night — before the briefing — to disclose concerns about the level of disease in a pen.
Ms McSweyn said the level of disease in pens was "very hard to know".
"P. salmonis will always be there as an endemic bacteria.
"There is no way of being clear of P. salmonis."
She said there had not been an increase in antibiotic resistance among farmed salmon, and that testing for this was continuing.
When asked if salmon with P. salmonis was continuing to be harvested for human consumption, Ms McSweyn said the disease was endemic.
The Natural Resources and Environment Department previously said the bacterium does not pose a risk to human health.
Four crossbench MPs — Greens leader Rosalie Woodruff, and independents Mr George, Craig Garland and Kristie Johnston — attended the briefing with agency officials.
They were concerned about whether the government had been able to obtain all relevant information from salmon companies over the extent of disease levels and mortalities.
Mr George said the industry needed greater reporting conditions over disease spread.
"What was made less clear today is exactly the extent of the disease outbreak, and that's because the … multinational fish farms do not have to tell anyone about the extent of the disease," he said.
The crossbenchers remain in negotiations with the Liberals and Labor ahead of a no-confidence motion on Tuesday to determine the next premier and government, and again called for greater regulations for the salmon industry.
When asked if the ongoing and evolving use of antibiotics was sustainable for the farmed salmon industry, Mr Pearce said it was common in agricultural sectors.
"In my humble opinion, science continues to evolve every day," he said.
"If I took you back 10 years, most of the antibiotics [and] medication that you would have been prescribed 10 years ago is no longer available."
In a statement, industry body Salmon Tasmania said intended new treatments would form part of a range of actions to combat P. salmonis.
"New actions include improved vaccines, stronger biosecurity, feed adjustments, on-farm innovations, and new treatment options," the statement reads.
