Salmon Aquaculture in New Zealand

Origins and Species

There are three species of salmon in New Zealand: Chinook salmon Oncorhynchus tschawytscha, Sockeye salmon Oncorhynchus nerka, and Atlantic salmon Salmo salar.

Only Chinook salmon (also known as "Quinnat" or "King Salmon") are successfully farmed on a significant scale in New Zealand. This is in contrast to the rest of the world where salmon aquaculture is focused on Atlantic salmon, except for some chinook salmon in Canada and Coho salmon in Chile. "King Salmon" is the name commonly used for chinook by the salmon farming industry and markets.

New Zealand has no native salmon or trout and all the salmonids were originally imported as ova. Although there is a very significant recreational trout fishery in New Zealand often sustained by hatchery output, farming of trout in New Zealand is illegal. Attempts have been made to farm the sockeye and Atlantic species in New Zealand but for various reasons these were unsuccessful such that only Chinook is now farmed.

The Chinook salmon we have today were successfully introduced by the Marine Department in the hope of starting a commercial rod fishing and canning industry although this never developed. Those introductions were via a hatchery on the Hakataramea River, between 1901 and 1907 these imports were from the Baird Fish Station on the McLeod River a tributary of the Sacramento River in California. An earlier attempt to introduce chinook salmon was made for a recreational fishery by the Hawkes Bay Acclimatisation Society in 1875 (these fish were released in the rivers of the Auckland Acclimatisation Society) but this and several other attempts in various parts of New Zealand are regarded as having been unsuccessful. Chinook salmon became established with self sustaining returns to rivers on the east coast of the South Island and to a minor extent on the west coast of the South Island. Further imports of live salmon into New Zealand have not been permitted for over 50 years. Ova was exported to Australia between 1910 and 1946.

Interest in salmon farming grew steadily during the 1970s as part of a worldwide trend towards commercial aquaculture. New Zealand’s first commercial salmon farm was established in 1976 as an ocean ranching venture at Waikoropupu Springs in Golden Bay, and made its first sales of freshwater-reared salmon in 1978. Other early ocean ranching farms included an ICI/Wattie joint venture on the lower Clutha River, and larger-scale hatcheries on the Rakaia River and the nearby Tentburn coastal site. The first sea-cage salmon farm was established in 1983 in Stewart Island’s Big Glory Bay by BP New Zealand Ltd. This was soon followed by the development of farms in the Marlborough Sounds.

Production of farmed salmon in 2004 was about 7,450 tonnes worth approximately $73 million, from less than 10 hectares of surface structures of seafarms plus freshwater farms. This compares with $163 million for farmed mussels, produced from 4,146 hectares of farms (2003).

Most production tonnage originates from sea cage farms located in the Marlborough Sounds and Stewart Island. Individual farm sites produce up to approximately 1,500 tonnes of salmon. There is another boutique marine farm in Akaroa Harbour. Freshwater farms are all in the South Island and tend to be smaller than marine farms. One novel situation, possibly unique in the world, is the establishment of farms within hydroelectric canals in the Mackenzie Basin.

Existing capacity of the industry is approximately 10,000 tonnes with the capacity for expansion to at least 14,000 tonnes. Currently there are 14 ongrowing sites and 12 hatcheries/freshwater sites, with an estimated juvenile fish production capacity of 10 million smolts.

Worldwide the growth of salmon aquaculture has been dramatic, with production increasing from 150,000 tonnes in 1988 to over 1,500,000 tonnes in 2004. Atlantic salmon represent approximately 80% of this total. Other species farmed around the world are Coho and Rainbow trout. New Zealand accounts for around half of worldwide farmed Chinook salmon production.

Salmon aquaculture is now undertaken in two main ways: freshwater rearing and sea cage rearing. A third farming method called ocean ranching is no longer actively pursued in New Zealand on a commercial scale. All three methods begin by collecting eggs and milt from captive broodstock, incubating the fertilised eggs in a freshwater hatchery (usually at 10-12 ºC), and rearing the newly hatched fry for a further 6-12 months. In freshwater and sea cage operations, the young fish (or smolt) are then transferred to larger cages or ponds where they are reared for the remainder of their lives. Fish remain in captivity for two to three years, and are typically harvested at weights of between 2 and 4 kg.

Although no longer pursued, ocean ranching required large numbers of smolts to be released to sea to fend for themselves before reaching adulthood, then relying on their legendary homing ability to guide them back to their point of release to be harvested. Several companies attempted this potentially efficient style of farming during the 1980s, but abandoned it when marine survival rates proved too low and inconsistent to sustain a commercially viable return.

New legislation was passed in late 2004 and came into effect on 1st January 2005. The aquaculture law reforms have bought about some major changes to the way aquaculture is managed in New Zealand. The most significant being that marine farming is now mostly covered by the Resource Management Act 1991. Previously there was a two stage process requiring both a permit from council then a separate permit from the Ministry of Fisheries, now there is one. Only minor change has been made to the Freshwater Fish Farming Regulations 1983. These regulations licence landbased and freshwater farms and are to be reviewed. Further information on the Aquaculture Law reform is available on the Ministry for the Environment website www.mfe.govt.nz.

Approximately 50% of New Zealand salmon production is exported. The main export market is Japan with supply also to the rest of the Pacific rim countries including Australia. The bulk of product to Japan is in either a gilled and gutted, or headed and gutted product form, with some other product forms such as smoked salmon. The local market demands a higher percentage of added value product such as steaks, fillets, smoked, gravlax, or kebabs. As harvesting of wild fisheries reaches the limits of sustainable harvesting, farmed fish such as salmon will have to provide an increasing proportion of fish products consumed.

Further information on salmon and the introduction of salmon farming in New Zealand can be found in the following books, available from public libraries:

McDowall, R.M. 1990. New Zealand freshwater fishes: A natural history and guide. Heinemann Reed, Auckland. 553p.

McDowall, R.M. 1994. Gamekeepers for the nation. Canterbury University Press, Christchurch. 508p.

Information prepared by Mark Gillard (The New Zealand King Salmon Company Ltd) and Nelson Boustead (National Institute of Water and Atmospheric Research Ltd - NIWA)