The linear growth of soft-shell clams, Mya arenaria L., has been studied at six locations in the White Sea, situated in the middle and low tidal zones. The main aim was to analyze the growth heterogeneity, both within beds (with respect to individual growth) and between beds (with respect to group growth). It was found that the Mya population was characterized by slow growth and high lifespan. Observed maximum shell size was 70-80 mm and longevity was at least 25 years. In addition, the heterogeneity in growth rates was high. Statistically significant differences in growth rate were found both within the beds and between the beds. No differences were found in group growth between different tidal horizons of the same site. The slowest growth of soft-shell clams was observed at sites with greatest content of fine particles (silt and clay) in sediments. Differences between beds in Mya group growth could reflect variability of nutritional conditions, which were probably determined by some peculiarities of local h