“In the medium term, while appropriate future stocking levels for Macquarie Harbour are reviewed, we may halve the input of Tassal smolt into the harbour to approximately 1 million to ensure its sustainability,”  chief executive Mark Ryan said on Wednesday.

It started destocking a lease in January after detection of non-compliance.

Rival Huon Aquaculture has launched court actions relating to federal conditions on fish farming in the harbour and a biomass limit.

Tassal confirmed it would oppose the orders sought by Huon Aquaculture.

Mr Ryan said Tassal remained committed to protecting the harbour to ensure sustainability, including for maintaining West Coast jobs.

Tassal reported net profit after tax of $27.7 million for the six months to December 31, up  9.6 per cent on the same period a year earlier.

Mr Ryan said an increase in biomass was expected to underpin strong growth in 2017-18.