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The aquaculture of salmonids is the farming and harvesting of salmonids under controlled conditions for both commercial and recreational purposes. Salmonids (particularly salmon and steelhead), along with carp, are the two most important fish groups in aquaculture.〔 The most commonly commercially farmed salmonid is the Atlantic salmon. In the U.S. Chinook salmon and rainbow trout are the most commonly farmed salmonids for recreational and subsistence fishing through the National Fish Hatchery System. In Europe, brown trout are the most commonly reared fish for recreational restocking.〔(【引用サイトリンク】title=Cultured Aquatic Species Information Programme Salmo trutta )〕 Commonly farmed non-salmonid fish groups include tilapia, catfish, sea bass and bream. In 2007 the aquaculture of salmonids was worth US$10.7 billion globally. Salmonid aquaculture production grew over ten-fold during the 25 years from 1982 to 2007. Leading producers of farmed salmonids are Norway with 33 percent, Chile with 31 percent, and other European producers with 19 percent.〔FAO: (World Review of Fisheries and Aquaculture 2008 ) Rome.〕 There is currently much controversy about the ecological and health impacts of intensive salmonids aquaculture. There are particular concerns about the impacts on wild salmon and other marine life. Some of this controversy is part of a major commercial competitive fight for market share and price between Alaska commercial salmonid fishermen and the rapidly evolving salmonid aquaculture industry.〔 ==Methods== The aquaculture or farming of salmonids can be contrasted with capturing wild salmonids using commercial fishing techniques. However, the concept of "wild" salmon as used by the Alaska Seafood Marketing Institute includes stock enhancement fish produced in hatcheries that have historically been considered ocean ranching. The percentage of the Alaska salmon harvest resulting from ocean ranching depends upon the species of salmon and location,〔(【引用サイトリンク】publisher=Alaska Department of Fish and Game )〕 however it is all marketed as "wild Alaska salmon". Methods of salmonid aquaculture originated in late 18th century fertilization trials in Europe. In the late 19th century, salmon hatcheries were used in Europe and North America. From the late 1950s, enhancement programs based on hatcheries were established in the United States, Canada, Japan and the USSR. The contemporary technique using floating sea cages originated in Norway in the late 1960s.〔 Salmonids are usually farmed in two stages and in some places maybe more. First, the salmon are hatched from eggs and raised on land in freshwater tanks. When they are 12 to 18 months old, the smolt (juvenile salmon) are transferred to floating sea cages or net pens anchored in sheltered bays or fjords along a coast. This farming in a marine environment is known as mariculture. There they are fed pelleted feed for another 12 to 24 months, when they are harvested. Norway produces 33 percent of the world's farmed salmonids, and Chile produces 31 percent.〔 The coastlines of these countries have suitable water temperatures and many areas well protected from storms. Chile is close to large forage fisheries which supply fish meal for salmon aquaculture. Scotland and Canada are also significant producers.〔(【引用サイトリンク】publisher=World Wildlife Fund )〕 Modern salmonid farming systems are intensive. Their ownership is often under the control of huge agribusiness corporations, operating mechanized assembly lines on an industrial scale. In 2003, nearly half of the world’s farmed salmon was produced by just five companies. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Aquaculture of salmonids」の詳細全文を読む スポンサード リンク
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