Growth rate and age at sexual maturity of Atlantic salmon smoltifying at one and two years of age
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Postsmolt growth rate and age at first maturation are compared for sibgroup or population groups of salmon originating from Norwegian rivers and fish farms. Generally high correlations were found between corresponding values (lengths at different ages and proportions of mature fish in the second and third sea year) for one and two year smolt. One year smolts were smaller at the smolt stage and grew slower the first sea year, but the two categories reached practically the same total length after two years in the sea. In most groups and in the total material one year smolt gave higher proportions of grilse. Proportions of mature fish during their third sea year were similar for one and two year smolt of the same groups. Pronounced variations between sibgroups and population groups were found both in growth rate and mean age at first maturation. This variation was much bigger than the variation between one and two year smolt of the same sib group.