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|synonyms_ref = 〔(【引用サイトリンク】title=Synonyms of Oncorhynchus mykiss (Walbaum, 1792) )〕 }} The rainbow trout (''Oncorhynchus mykiss'') is a trout and species of salmonid native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coastal rainbow trout or Columbia River redband trout that usually returns to fresh water to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead. Adult freshwater stream rainbow trout average between , while lake-dwelling and anadromous forms may reach . Coloration varies widely based on subspecies, forms and habitat. Adult fish are distinguished by a broad reddish stripe along the lateral line, from gills to the tail, which is most vivid in breeding males. Wild-caught and hatchery-reared forms of this species have been transplanted and introduced for food or sport in at least 45 countries and every continent except Antarctica. Introductions to locations outside their native range in the United States (U.S.), Southern Europe, Australia, New Zealand and South America have damaged native fish species. Introduced populations may affect native species by preying on them, out-competing them, transmitting contagious diseases (such as whirling disease), or hybridizing with closely related species and subspecies, thus reducing genetic purity. Other introductions into waters previously devoid of any fish species or with severely depleted stocks of native fish have created world-class sport fisheries such as the Great Lakes and Wyoming's Firehole River. Some local populations of specific subspecies, or in the case of steelhead, distinct population segments, are listed as either threatened or endangered under the Endangered Species Act. The steelhead is the official state fish of Washington.〔(【引用サイトリンク】title=Symbols of Washington State )〕 ==Taxonomy== The scientific name of the rainbow trout is . The species was originally named by German naturalist and taxonomist Johann Julius Walbaum in 1792 based on type specimens from the Kamchatka Peninsula in Siberia. Walbaum's original species name, ''mykiss'', was derived from the local Kamchatkan name used for the fish, ''mykizha''. The name of the genus is from the Greek ''onkos'' ("hook") and ''rynchos'' ("nose"), in reference to the hooked jaws of males in the mating season (the "kype").〔 Sir John Richardson, a Scottish naturalist, named a specimen of this species in 1836 to honor Meredith Gairdner, a Hudson's Bay Company surgeon at Fort Vancouver on the Columbia River who provided Richardson with specimens. In 1855, William P. Gibbons, the curator of Geology and Mineralogy〔(【引用サイトリンク】title=Invertebrate Zoology and Geology )〕 at the California Academy of Sciences, found a population and named it (Latin: rainbow), later corrected to . These names faded once it was determined that Walbaum's description of type specimens was conspecific and therefore had precedence. In 1989, morphological and genetic studies indicated that trout of the Pacific basin were genetically closer to Pacific salmon (''Oncorhynchus'' species) than to the ''Salmos'' – brown trout or Atlantic salmon of the Atlantic basin. Thus, in 1989, taxonomic authorities moved the rainbow, cutthroat and other Pacific basin trout into the genus ''Oncorhynchus''. Walbaum's name had precedence, so the species name became the scientific name of the rainbow trout. The previous species names ''irideus'' and ''gairdneri'' were adopted as subspecies names for the coastal rainbow and Columbia River redband trout, respectively.〔 Anadromous forms of the coastal rainbow trout or redband trout are commonly known as steelhead.〔 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「Rainbow trout」の詳細全文を読む スポンサード リンク
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