This paper is based on experiments to test if differences in migratory behaviour of Norwegian coastal cod and north east Arctic cod is related to parental origin or, alternatively, is related to the environmental experienced during the premature stages. Earlier experiments have shown that when wild fish from the two groups are transplanted and released at a new location, their behaviour after release differ distinctly. The two groups of cod in the present study were raised in captivity under identical conditions. Mature fish were tagged with acoustic transmitters and their behaviour studied during a week's period after release. Methods and design were the same as in the earlier experiments, and the results signified no behavioural differences between the two groups of fish. This might be an indication of strong environmental influence on migratory behaviour in cod. The number of released fish were low and the results have to be verified by new trials.