Interpopulation comparison of size and age at smolting of white-spotted charr, Salvelinus leucomaenis

The relationships between size and age at smolting and juvenile growth rates were examined for 13 populations of white-spotted charr (Salvelinus leucomaenis). Mean smolt length (ranging 142-210 mm in fork length) and smolt age (2.4-3.7 years) varied significantly among populations and there was a significant negative relationship between smolt length and age. Mean smolt length was positively correlated with mean specific growth rate from age 0 to 1 year, whereas mean smolt age was negatively correlated with specific growth rate. The present study shows that the freshwater environment conditions operating on juvenile growth are important for moulding the phenotypic characteristics of size and age at smolting.