ABC reports that representatives from the three Tasmanian salmon companies involved in the expansion - Tassal, Huon Aquaculture and Petuna - were on hand to hear the announcement, which was made in Strahan.
Under the discussed plan, fish farming in Macquarie Harbour will double, but the total area under salmon production will total around three per cent of the harbour.
West Coast Mayor Darryl Gerrity said the announcement will mean that hundreds of job opportunities in the short and long term will become a possibility.
According to Mr Gerrity, the job opportunities could convince many families to relocate to the west coast after the experience of the past few years where jobs have been scarce.
He said the infrastructure projects planned will greatly improve the waterfront area around Strahan and create jobs in many service industries.
The Mayor said the area will become an aquaculture hub.