The aim of the study was to determine the growth and survival of juvenile pike, Esox lucius L., reared in recirculating aquaculture systems (RAS) and then released into earthen ponds. Three different sizes of fish were used in the experimental releases of stocking material with mean body weights of 1.5 g (group S), 7.0 g (group M), and 18.5 g (group L) which were reared in a recirculating aquaculture system and fed formulated feed exclusively. Before the fish were released, they were tagged with visible implant elastomer (VIE) tags. The highest final body weight was attained by the fish in group S, the mean body weight of which was 85.5 g, which was significantly statistically higher than in the other groups (P < 0.001). No differences in survival were noted among the groups. Positive biomass increases were only exhibited in group S (37 kg ha-1), and it was highly statistically significantly greater than it was in the other groups (P < 0.001). The results of the experiment could indicate that the suitability of juvenile pike for stocking depends on its size at release. Extending the rearing period in RAS resulted in poorer stocking results in the ponds.
