Tasmania's premier has accused the federal government of trying to kill off the state's salmon farming industry and the hundreds of jobs it provides.
Simmering tensions between the two governments erupted on Tuesday after the federal environment minister wrote to Premier Jeremy Rockliff, warning of a possible "pause" to salmon farming in Macquarie Harbour.
The harbour is the only place on earth where the Maugean skate exists.
But experts warn the ancient fish is on the brink of extinction, threatened by poor water quality mainly associated with salmon farming, but also other uses.
In her letter to the premier, federal Environment Minister Tanya Plibersek expressed serious concerns about the industry's plan to help the skate.
Conservation advice has said reducing salmon loads is the fastest and simplest way to fix the water quality problems but the industry has refused to do that.
Instead it's planning a trial that will use a barge and pumps to oxygenate the harbour, hoping to offset what farmed salmon suck out.
Ms Plibersek told the premier the oxygenation trial alone won't fix things, and other recommended actions - including cutting salmon loads - will be important.
The minister also said her department has been asked to reconsider if salmon farmers have the federal environmental approvals needed to keep operating.
If it's found they don't, a possible outcome could be a "pause" in farming in the harbour while approvals are sought.
Late on Tuesday, Mr Rockliff said his Liberal government would fight for the industry.
"I will not stand by and allow the federal Labor government to kill off our salmon industry and the more than 350 jobs that it supports.
"Our government backs our salmon industry 100 per cent."
Earlier Tasmania's Environment Minister Roger Jaensch told Ms Plibersek to take her finger "away from that trigger" and work with the state government, salmon farmers and scientists to boost harbour health.
"This could all be determined by environmental organisations outside of Tasmania, putting pressure on her. She needs to be listening to Tasmanians."
In her letter, Ms Plibersek said The Australia Institute, the Bob Brown Foundation and the Environmental Defenders Office had queried whether salmon farmers had the federal environmental approvals needed to continue operating.
She said if any of the three requests were deemed valid, she'd be required under federal laws to formally reconsider what's happening in the harbour.
That process would involve broad consultation and would take into account "any measures taken by the industry or others to help protect the skate".
"If the reconsideration finds that the salmon industry in Macquarie Harbour does not have the necessary environmental approvals the EPBC Act ... would require operations to pause while approvals are sought."
Ms Plibersek went on to say she'd do what she could to get the salmon industry onto "a truly sustainable footing".
Salmon Tasmania, which represents the state's biggest producers, declined AAP's request for an interview but chief executive Luke Martin told ABC radio he's disappointed in the minister.
Last week, it emerged the industry's plan to oxygenate the harbour is yet to secure all the funded required, a month before work is due to start.
Salmon Tasmania expects the trial to cost $6 million to $7 million. It has promised about half but expects the federally-funded Fisheries Research and Development Corporation to provide the rest.
The statutory corporation, also funded by fishing industry contributions, last week said it hadn't received a funding application but was expecting one soon.
