The worlds' largest producer and market supplier of the Chinook salmon is New Zealand
. Marketed as King Salmon, in 2009, New Zealand exported 5,088 tonnes of salmon equating to a value of NZ$61 million in export earnings. For the year ended March 2011, this amount had increased to NZ$85 million., New Zealand accounts for about half of the global production of Chinook salmon
, and about half of New Zealand's production is exported. Japan is New Zealand's largest export market, with stock also being supplied to other countries of the Pacific Rim, including Australia.
Farming of the species in New Zealand began in the 1970s, where hatcheries were initially set up to enhance and support wild fish stocks with the first commercial operations initiating in 1976. After some opposition against their establishment by societal groups, including anglers, the first sea cage farm was established in 1983 at Big Glory Bay in Stewart Island
by British Petroleum
NZ Ltd. Today, the salmon are born in land-based hatcheries (of which there are several) and transferred to sea cages or freshwater farms, where they are grown out to harvestable size of 3 – 4 kg. The broodstock
for the farms are usually selected from existing farm stock or sometimes sourced from wild populations. Eggs and milt
are stripped manually from sexually mature salmon and incubated under conditions (of approximately 10 – 12°C), replicating the streams and rivers where the salmon would spawn naturally. After hatching, the baby salmon are typically grown to smolt stage (around six 6 months of age) before they are transferred to the sea cages or ponds. Most sea cage farming occurs in the Marlborough Sounds
, Stewart Island and Akaroa
Harbour, while freshwater operations in Canterbury
use ponds, raceways and hydro canals for growout operations. Low stocking densities, ranging between less than 1 kg/m3 to around 25 kg/m3 (depending on the life stage of the salmon) and the absence of disease in the fish means New Zealand farmers do not need to use antibiotics or vaccines to maintain the health of their salmon stocks. The salmon are fed food pellets of fish meal
specially formulated for Chinook salmon (typical proportions of the feed are: 45% protein, 22% fat, 14% carbohydrate plus ash and water) and contain no steroids or other growth enhancers.