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The Rainbow Trout

The rainbow trout (Salmo gairdneri), most widely distributed member of the trout family, is one of the five top sport fishes in North America. In addition, it supports a cottage fish farming industry in the three Prairie Provinces.

Originally a native of the Pacific coast drainage system from Mexico to Alaska, it is now found in every Canadian province as a result of stocking. It was introduced to Saskatchewan waters in 1924; Manitoba waters in 1938; and Alberta waters in 1958. Large, sea-run rainbows on the Pacific coast are known as steelheads. A landlocked variety in the interior of B.C. is called the Kamloops trout. The rainbow has an elongated body, with an iridescent, reddish band running along each side from head to tail. Both the colour and size of this fish vary with the environment. In the sea-run type, the back is dark blue, with sides and underparts silvery. In the non-migratory type, the back is bluish to olive green shading to silvery green on the sides and white over the belly. The colour of the lateral stripe varies from light pink to a vivid red or reddish purple and is most pronounced in mature fish, especially breeding males. Sides, tail and dorsal fins are profusely dotted with small, dark spots.

In general, large rainbows are caught in large bodies of water and small ones in streams and ponds. Stream-caught fish usually weigh under 0.45 kg, while fish from the rivers and lakes weigh between 0.91 and 2.27 kg. Rainbows that have migrated to sea or a large inland lake such as one of the Great Lakes (steelheads), on return may weigh 6.8 to 9.07 kg, although most weigh between 3.6 and 4 kg. The present angling record topped the scales at 16.8 kg and measured 103 cm. It was taken from Lake Pend Oreille, Idaho, in 1947.

The rainbow trout is well adapted to both streams and lakes. While it prefers cold, clear, swift-flowing water, it can tolerate warm water. Prairie farmers, especially in Manitoba, now make use of many small, glacier-formed pothole lakes as rainbow-trout-rearing ponds. With some success, they are cropping these lakes annually and selling the fish to local markets.

Apart from fish farming ventures, there is no commercial fishery for rainbow trout in the mid-west region. But the game fish qualities of the rainbow make it a very valuable species. Its beauty, strength, endurance and spectacular leaps have endeared it to anglers. And it is a prize worth striving for, as its flesh, which varies in colour from bright red to white, has exceptionally fine favour.

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Last updated: 2006-06-06

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