The
rainbow trout (
Oncorhynchus mykiss) is a species of
salmonid native to tributaries of the
Pacific Ocean in
Asia and
North America. The
steelhead is a sea run rainbow trout (
anadromous) usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species. The fish is sometimes called a
salmon trout. Several other
fish in the salmonid family are called
trout, some are anadromous like salmon, whereas others are resident in freshwater only.
The species has been introduced for food or sport to at least 45 countries, and every continent except
Antarctica. In some locations, such as
Southern Europe,
Australia and
South America, they have negatively impacted
upland native fish species, either by eating them, outcompeting them, transmitting contagious diseases, (like
Whirling disease transmitted by
Tubifex) or hybridization with closely-related species and subspecies that are native to western
North America.
Salmo marmoratusSalmothymus obtusirostris salonitana
Taxonomy
The species was originally named by
Johann Julius Walbaum in 1792 based on type specimens from
Kamchatka. Richardson named a specimen of this species
Salmo gairdneri in 1836, and in 1855, W. P. Gibbons found a population and named it
Salmo iridia, later corrected to
Salmo irideus, however these names faded once it was determined that Walbaum's type...
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