Australian salmon and trout producer Petuna may be small in the grand scale of seafood production, but its ambitions to double production in an offshore farm site in Tasmania's ominously named Storm Bay mark a bigger future for the company.

For Petuna, as it is for many Australasian salmon producers facing increasingly warm water temperatures, the future is offshore, and the company's new 8,000 metric-ton site will double its production.

It's been a long time in the works, but the recent approval of Petuna's proposed Storm Bay site, 11.5