A decade ago New Zealand salmon was sold as a frozen commodity and its shift to a premium brand delicacy roughly coincides with the involvement of private equity.
Direct Capital took a 43 per cent stake in King Salmon three years ago and "they've really added huge value to the business - they bring more than capital to the table", says Rosewarne.
"At the time, we absolutely needed good management expertise and they challenged us about markets and the product mix; they've brought disciplines and structures to the business."
King Salmon is now pushing its wares in Japan and North America (and 10 other markets), using professional chefs to get the premium product into Michelin-starred restaurants and upmarket food stores.
Rosewarne says the company tends to grow by about 10 to 15 per cent a year, mainly through increased production.
Last year, however, it increased revenue by achieving higher prices.
A new brand for King Salmon will be unveiled this year to help lift market share, particularly in the US. Changes to aquaculture regulations mean Rosewarne hopes to more than double its operation in Marlborough from 7ha of the sea's surface to 15ha.
"Our ambition is global," he says.