Blue lipped mussels are considered a pest by Marlborough aquaculture companies.
They grow near the top of the mussel lines above the favoured green mussels and are thrown away.
But Jonathan Large, president of the Marine Farming Association, is part of a group exploring ways to use and make money from the blue mussels.
Blue mussels are generally smaller, have a stronger taste and different texture, and are consumed in many countries overseas but don’t fit within the New Zealand $170 million green lipped mussel industry.
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Large is part of the Smart and Connected Aquaculture initiative investigating ways of turning the blues into a slurry which could be used in pet foods, fertilisers and various applications.
Other members of the initiative include chairman Zane Charman, manager mussel farming at Sanford, and Andy Elliot, research and business development manger at Maori food and beverage producer Kono, an associated company of Nelson tribal group Wakatu Incorporation.
Large said there is big potential for the blue mussels, currently considered a waste stream.
“They occur naturally in the Marlborough Sounds and they’re edible but they don’t fit with the more specialised market for greens. They’re considered weeds,” Large said.
“They’re inter-tidal which means they thrive in that part of the water column affected by tides. That’s also why they’ve evolved their colour because they get more sunlight. Even greens get darker near the surface.
“Their presence on the mussel lines is wildly variable. Sometimes there are none and on other lines they can virtually take over and the line has to be re-seeded or they affect growth rates of the greens,” Large said.
A related Marine Farming Association project funded by the government sustainable farming fund has been researching the distribution, abundance and farming implications associated with the competition between the two mussel varieties.
The aim is to reduce the incidence of blues on the mussel lines requiring less grading on boats and factories and dumping in landfills.
Other mussel by-product experiments by Lincoln University researchers in collaboration with Kono using Callaghan Innovation funding involved placing crushed shells beneath grape vines to control grass grubs and brown beetles which affect yields. The alternative is to spray them with pesticides.
Marlborough produces about 65 per cent of New Zealand mussel production with processing mainly at Havelock by Sanford and at Blenheim in factories run by Kono and Talley’s, while some of them are sorted at Havelock by a Talley’s subsidiary and sent for oil and powder nutraceuticals in Nelson and Christchurch.