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Choice of Colors of Food Items by Rainbow Trout ( Salmo gairdneri )

1973; Canadian Science Publishing; Volume: 30; Issue: 2 Linguagem: Inglês

10.1139/f73-040

0015-296X

R. M. Ginetz, Peter Larkin,

Reproductive biology and impacts on aquatic species

Rainbow trout in artificial stream situations were offered seven colors of dyed rainbow trout eggs in all combinations of two colors. Against a pale, greenish-blue background, in daylight, the color preference was: blue, red, black, orange, brown, yellow, and green. This order largely reflected contrast with background color; but, in addition, there were preferences for certain colors. Particular color combinations such as yellow and black, and yellow and blue, resulted in significantly higher total consumption. When background color was varied, preference was low for the color of eggs that matched the background, but the effect was not statistically demonstrable. At low light intensities the order of preference for various colors was yellow, red, blue, and black. The results collectively indicate keen color discrimination in rainbow trout and preferences for particular colors in particular environmental settings. These findings could have useful application to field situations where it is desirable to modify rates of predation on salmon fry by presenting other kinds of food to satiate predators.