Research comes out of a shell

Farming mussels has always been a haphazard affair, but now New Zealand scientists have managed to coax them to breed in captivity.

The first of 500 tonnes of the greenshell mussels from a joint Government-private company programme are about to be harvested in the Marlborough Sounds.

The research promises to give farmers more certainty over growing the indigenous shellfish, worth $350 million to the economy. Once the programme is in full swing, SPATNZ’s hatchery in Nelson could produce about 30,000 tonnes a year of adult mussels, adding $200m value. Last year the industry produced just over 80,000 tonnes. Traditionally, mussel ‘‘babies’’ or spat washes up on beaches such as 90-Mile Beach attached to seaweed and is bagged for farmers. Sometimes farmers put out lines from buoys and hope the spat will attach to them. But that has made life difficult for farmers, who have to hope they will have enough spat for their farms from year to year.

Getting the mussels to give up their secrets was not easy, said scientist and SPATNZ head, Rodney Roberts.

‘‘We experimented with lighting, different bath temperatures and sounds and we finally settled on a combination of light, temperature and small vibrations that seems to really get the mussels going, encouraging them to produce maximum quantities of sperm and eggs.’’

Roberts said consumers would benefit from the captive-reared mussels as they would be a more consistent size.

The SPATNZ hatchery is the result of a collaboration between the Ministry for Primary Industries (MPI) and seafood company Sanford.