TRD: Animal Production: AQUACULTURE: TROUT
Rainbow Trout (Onchorhyncus mykiss)
Rainbow Trout (Onchorhyncus mykiss)
Description
Trout belong to the group of fishes known as Salmonids. The term Onchorhyncus means hooked nose, which refers to marked snout and kype possessed by most of the female at spawning. They are called rainbow trout because of their varied colors. Typical coloration of rainbow trout is blue to olive green above the lateral line, a pink band along the lateral line and silver below the lateral line. The back, sides, head and fins are generally covered with small black spots.
Distribution
Rainbow trout have been introduced to mountain streams and upland reservoirs of the Western and Eastern Cape, Kwazulu-Natal, north-eastern Free State, Mpumalanga, Limpopo province, Swaziland, Lesotho and Zimbabwe. Trout have been widely introduced in temperate and high altitude regions throughout the world.
Biology
Trout feed on wide range of animal foods from small invertebrates including aquatic insects, especially mayfly nymph, caddis fly and midge larvae; to terrestrial and aerial insects, crabs, frogs and fish. Due to its fast growth and ease of domestication, it was the first salmonid to be used for large scale production. Salmonids are cold water fish. Another fact that makes it more suitable candidate for aquaculture is the fact that it is not as sensitive to temperature and water quality changes as brown trout is and is much more resistant to the majority of salmonid disease. They breed later in the season than brown trout i.e. from June through to August and even December. Breeding fish move upstream to suitable gravel beds. The female digs a redd by beating her body and tail rapidly over the gravel. Spawning takes place in the redd and usually several redds are build and used by a female before she is spent.
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