Fish stock limits at Macquarie Harbour will be further reduced, but producers could still be allowed to exceed this cap if waste collection systems are approved.
On Friday, Environment Protection Authority director Wes Ford handed down his draft determination of a new biomass limit at the harbour.
Mr Ford said the cap would be reduced from 14,000 to 12,000 tonnes for the year from June 1, but salmon producers would be able to exceed this if a trial in-water solid waste collection system was installed under the pens and then approved.
Mr Ford said the system would be trialed by Tassal and cost about $500,000.
“The alternate for Tassal is to remove about 4000 tonnes of fish,” he said.
“In economic terms, that’s more than $60 million of fish currently in the harbour that, had I not allowed them to grow them through, would obviously impact on the economy of the state, the economy of the West Coast and the community.
“I have determined that it is appropriate to allow the fish to be grown under a system where the fish waste is collected and removed from the harbour and disposed of appropriately.”
But Environment Tasmania strategy director Laura Kelly said she was “alarmed” by the decision.
“There’s been no environmental impact assessment released, there is absolutely no evidence to suggest that faecal mounds on top of a tarp will be any less damaging to oxygen levels in the harbour than faecal mounds on the seafloor,” she said.
Tassal said Mr Ford had balanced the environmental, economic and social needs of the community.
“Tassal will adaptively manage its remaining fish stocks and will further minimise environmental impacts of its Macquarie Harbour salmon farming operations through the installation of waste capture liners,” it said.
Tassal was previously forced to destock its Franklin lease at Macquarie Harbour after damage was done to the World Heritage Area.
Huon Aquaculture, who called for a 10,000-tonne biomass cap, said it would take time to consider the news, given its complexity.
Petuna Aquaculture acting chief executive David Wood welcomed the decision to move towards a lease-by-lease framework.
“By seeking to move towards a lease-based management framework, a model Petuna has supported for some time, [Mr Ford] is ensuring each company is held accountable for their individual operations,” he said.
Primary Industries Minister Jeremy Rockliff said the determination proved the system was working.
“We are confident our toughened changes to the regulatory framework and the independent oversight provided by the EPA will ensure this world-class industry remains sustainable, responsible and accountable,” Mr Rockliff said.