The rainbow trout 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 two to three years at sea; rainbow trout and steelhead trout are the same species. The fish are often called 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, (such as whirling disease transmitted by Tubifex) or hybridization with closely related species and subspecies that are native to western North America.
Like salmon, steelheads are anadromous: they return to their original hatching ground to spawn. Similar to Atlantic salmon, but unlike their Pacific Oncorhynchus salmonid kin, steelheads are iteroparous (able to spawn several times, each time separated by months) and make several spawning trips between fresh and salt water. The steelhead smolts (immature or young fish) remain in the river for about a year before heading to sea, whereas salmon typically return to the seas as smolts. Different steelhead populations migrate upriver at different times of the year. "Summer-run steelheads" migrate between May and October, before their reproductive organs are fully mature. They mature in freshwater before spawning in the spring. Most Columbia River steelheads are "summer-run". "Winter-run steelheads" mature fully in the ocean before migrating, between November and April, and spawn shortly after returning. The maximum recorded life-span for a rainbow trout is 11 years.
Rainbow trout are predators with a varied diet, and will eat nearly anything they can grab. Their image as selective eaters is only a legend. Rainbows are not quite as piscivorous or aggressive as brown trout or lake trout (char). Young rainbows survive on insects, fish eggs, and smaller fish (up to 1/3 of their length), along with crayfish and other crustaceans. As they grow, though, the proportion of fish increases in most all populations. Some lake-dwelling lines may become planktonic feeders. While in flowing waters populated with salmonids, trout eat varied fish eggs, including salmon and cutthroat trout, as well as the eggs of other rainbow trout, alevin, fry, smolt and even leftover carcasses.
Rainbow trout and steelhead are both highly desired food and sportfish. A number of angling methods are common. Rainbow trout are a popular target for fly fishers. Spinners, spoons, and small crankbaits can also be used productively, either casting or trolling. Rainbow trout can also be caught on live bait; nightcrawlers, trout worms, and minnows are popular and effective choices. The IGFA recognizes the world record for rainbow trout was caught on Saskatchewan's Lake Diefenbaker by Sean Konrad on September 5, 2009. The fish weighed 48 lb, 0 oz (21.77 kg). Many anglers consider the Rainbow trout the hardest fighting trout species, as this fish is known for leaping when hooked and putting a powerful fight.
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