What is aquaculture?
Aquaculture is the farming of fish and other animals and plants that live in water. It can take place in the sea, in lakes, rivers, and in special pools on land. New Zealand aquaculture is a multi-million dollar industry.
The main species farmed in New Zealand for export are mussels, salmon and oysters.
The future of aquaculture
More animals are being trialled for farming, including pāua and sea horses, which are used in Asian medicine.
Threats to aquaculture
The main threat to aquaculture is from growths of harmful algae, known as toxic blooms. Coastal waters are regularly tested.
Two toxic bloom disasters have hit the industry so far. In 1989, a bloom of poisonous plankton affected salmon farms in Stewart Island. Another widespread bloom grew in the summer of 1992–93, and people became sick from eating infected shellfish. The government closed all harvesting from mussel farms for several months, and growers banned moving young mussels from Northland beaches.
Following this, coastal waters and shellfish were monitored. The Ministry for Primary Industries manages this monitoring and ensures that water and shellfish samples are tested weekly.
Greenshell mussels
In the mid-1980s there were plenty of fresh green-lipped mussels and they were cheap in New Zealand supermarkets. The industry then looked at exporting mussels.
Frozen mussels in half shells became the main export item known as NZ Greenshell™ mussels. 
The main mussel farming areas are in the Coromandel and Marlborough Sounds. Stockings full of baby mussels (spat) are tied to rows of ropes, floating under buoys. The young mussels grow through the stockings and anchor themselves to the ropes.
Once mussels are harvested the ropes are re-seeded with wild baby mussels which are mostly found and collected from seaweed on Northland beaches.
Today SPATNZ (which stands for shellfish production and technology New Zealand limited) runs a programme funded by the government (MPI) and Sanford.
Greenshell™ mussels are only found in New Zealand. Until now, New Zealand’s mussel growers have relied on catching wild spat (baby mussels) around our coastline. SPATNZ are the first to try to selectively breed Greenshell™ mussels so mussel growers have the spat they need to grow the best mussels in the world.
During this field trip you will visit SPATNZ and see how they are breeding mussels.
