Salmon industry scrambling for solutions following fish deaths

The Tasmanian aquaculture industry is seeking advice from the state government to address an endemic bacteria that has persisted in salmon farms and has been responsible for recent fish deaths at a Huon Aquaculture pen in the D'Entrecasteaux Channel.

Piscirickettsia salmonis was responsible for a fish mortality event that occurred over the summer, during which chunks of dead salmon washed up on beaches in southern Tasmania.

The disease has persisted throughout the winter and the salmon industry is considering several approaches, including vaccine development, adjusting production strategies and improving fish health surveillance.

One of the proposed solutions is to use Florfenicol, an antibiotic that is not commonly used on salmon in Australia but has been in places such as Chile.

A spokesperson for Salmon Tasmania said it had been engaging with the state government about using the antibiotic since February.

The number of fish that have been killed is not known but it has not been reported as a mass mortality event, which is defined as when 0.25 per cent of a salmon pen dies over three days.

Primary Industries and Water Minister Gavin Pearce briefed Labor, the Greens, the crossbench and independent Legislative Council members about Piscirickettsia salmonis.

Independent MP Peter George said Premier Jeremy Rockliff had informed him about the situation with the bacteria before the briefing.

Mr Pearce said his government was taking the fish deaths seriously and that it was being closely monitored by the Department of Natural Resources and Environment (NRE).

“Animal welfare, biosecurity and the waterways must be at the forefront of everything industry does,” he said.

“I have been clear with industry there will be consequences if it doesn’t adhere to the strict rules and act in the best interest of Tasmanians.

“This is a reasonable expectation of any farmer or industry.

“We will compel companies to provide up-to-date information regarding any level of disease present in salmon across the state.”

Acting Chief Veterinary Officer for Tasmania, Deborah McSweyn, said following the summer mass mortality event that government and industry were determined to prevent the spread of Piscirickettsia salmonis.

“It’s a very complex multi-bacterial disease and we need to think about it on multiple fronts.

“And antibiotics, like in all livestock industries, will be one of those things – but antibiotics aren’t something we’re looking to lean on.

“It is simply a tool that we will use, as we do in every livestock industry, to prevent any decline in animal welfare and to protect those fish.”

NRE secretary Jason Jacobi said his department had been speaking with the aquaculture industry about what needed to be done to prevent a Piscirickettsia salmonis mortality event.

“It’s really become evident over these last six months that this new antibiotic, Florfenicol, has opportunities and we are hearing positive news about the potential for that to be used as an alternative to Oxytetracycline.

“There are concerns that the condition or the extent of Piscirickettsia salmonis D'Entrecasteaux Channel remains.

“We want to be alert to and aware of any cases where it might be causing the death or mortality of fish.

“Compliance actions are routinely undertaken by my department and they’re important for the intelligence that we gather.”

Greens Leader Rosalie Woodruff said she was concerned the recent salmon deaths foreshadowed what would happen next summer and was an indication that it was the new normal for fish farming in Tasmania.

“What the government has done in caretaker mode is sign off on an application to use a currently unregulated antibiotic to try and stop what is expected to be mass fish mortalities in the near future,” Dr Woodruff said.

“This is a terrible situation for the marine environment and it is exactly why we have all been so concerned to get some real changes to the environmental laws.”

Independent MP Craig Garland said he wanted to see a new marine plan established.

“All we’re asking is for proper regulation, for proper oversight and for full transparency, and we’ve got none of that so far.
“The tail is wagging the dog and Tasmanians expect a better management approach to this industry.

“It is extremely alarming to have a disease outbreak right now at this time of year.”