page_title: Aquaculture in New Zealand
section_title: Mussels
hierarchical_section_title: Aquaculture in New Zealand / Cultured species / Mussels
caption_attribution_description: Fresh New Zealand green mussels in glass tank
context_page_description: Aquaculture started to take off in New Zealand in the 1980s. It is dominated by mussels, oysters and salmon. In 2007, aquaculture generated about NZ$360 million in sales on an area of 7,700 hectares. $240 million was earned in exports.
  In 2006, the aquaculture industry in New Zealand developed a strategy aimed at achieving a sustainable annual billion NZ dollar business by 2025. In 2007, the government reacted by offering more support to the growing industry.
context_section_description: Until the early 1960s, mussels were harvested by hand from intertidal rocks. Dredging was then introduced, and within a few years the mussel beds in Tasman Bay and the Hauraki Gulf were dredged clean. In the late 1960s, following this collapse, the aquaculture of the New Zealand mussel began. The endemic green lipped mussel was used to trial growing mussel spat (young mussels) on ropes suspended from rafts. The Hauraki Gulf and the Marlborough Sounds provided sheltered environments, with clean water rich in plankton. The cultured mussels were ready for harvest after 12 to 18 months, and first went on sale in 1971.
  More growers entered the industry. The labour-intensive raft method was replaced with a modified Japanese longline system. Biodegradable stockings were packed with spat and tied to parallel rows of looped ropes, supported by buoys. Young mussels grow through the stockings, anchoring themselves to the ropes with their strong byssal threads (beards). The farms are usually located in sheltered or semi-sheltered areas where there is sufficient depth of water at low tide to keep the longline droppers off the bottom. Recent research has been investigating offshore mussel farming in exposed areas several kilometres from shore, such as farms offshore from Napier and Opotiki.
  Initially the ropes were allowed to reseed naturally, after harvest, from the spat already present in coastal waters. However, this method was unreliable. In 1974 a marine scientist discovered mussel spat encrusted on drift kelp on Ninety Mile Beach. Locals collected the seaweed and air freighted it to mussel farmers. Kaitaia spat, as it became known, is now the prime source of seed mussels. There are some experimental hatcheries.
  Improved techniques have led to rapid production increases, and bulk handling methods have been introduced to meet growing demand for export to more than 60 countries. By 2006 there were over 900 mussel farms in New Zealand covering about 6500 hectares, and worth about $224 million in annual sales. About $180 million were exports, usually sold as frozen mussels in half shells, patented with the trade name NZ Greenshell Mussels.
caption: Green lipped mussel in a tank
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