Tassal – Tasmania’s top salmon supplier – has been ordered to offload thousands of tonnes of stock.

Tasmania’s Environment Protection Authority (EPA) recently reduced stocking limits from 20,000 tonnes to 14,000 to address deteriorating conditions in Macquarie Harbour.

The EPA says conditions in the harbour are getting worse, with levels of beggiatoa bacteria increasing while oxygen levels drop.

Tassal has been ordered to destock one of its farming leases in the harbour – the closest lease to the nearby World Heritage Area.

The company is not impressed.

“Given the pending legal action and the fact that Tassal is considering its position with respect to this matter, Tassal is not in a position to make any comment about its operations in Macquarie Harbour,” it said in a statement.

“The lease is a double size lease. This was done to accommodate all of the companies fitting into the centre of the harbour, which was done to accommodate a clear path for the tourist operators.”

The order comes after Huon Aquaculture announced it will take the State Government to court over the amount of salmon it allows to be farmed in Macquarie Harbour.

Environment Tasmania strongly supports Huon Aquaculture's legal proceedings.

“The latest report from IMAS (Institute of Marine and Antarctic Studies) scientists shows that all marine life under Tassal's largest lease in Macquarie Harbour is dead,” it said in a statement.

“The Government knew this last November, but have allowed Tassal to farm in a dead zone until March this year.

“These legal proceedings provide some hope that action will be taken to protect Macquarie Harbour and the jobs that rely on it, and that some of the evidence sought by Environment Tasmania but declared 'commercial in confidence' by the Hodgman Government will finally come to light.”