Standard metabolic rate (R(S)), specific growth rate (G) and aggressiveness were investigated in three Finnish populations of Atlantic salmon Salmo salar (Neva, Saimaa and Teno), which were reared in identical hatchery conditions. The populations differed in their geographical origin and native habitat. There was a significant difference between populations in R(S): the southernmost Neva population had higher values in R(S) than the northernmost Teno population. No difference was found in G or aggressiveness between the populations. G was found to have a significant positive association with aggressiveness and R(S) among the three populations, however, these results were not statistically significant after correction for multiple tests. There was no significant association between R(S) and aggressiveness. Higher metabolic rate of the most southern population Neva is suggested to be an adaptation to the more abundant food sources of the southern stream.