The Past: Learning and Genetics
The events of the past have affected the migratory behaviour of fishes through two major pathways. During the life of individual fish, behaviour will have been altered by learning. On the time-scale of generations, natural selection will alter the behaviour of the population. These two mechanisms interact with each other. Natural selection will favour the survival and reproduction of those individuals with the ability to learn and remember specific important information such as the odour of a home stream. Life history traits such as life span, reproductive rate and development rate are also under some degree of genetic control and therefore are subject to natural selection (Cole 1954; Allendorf and Utter 1979; Schaffer 1979; Ryman 1981).
KeywordsChinook Salmon Fish Stock Pink Salmon Genetic Stock Cutthroat Trout
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