Impact of light intensity on the results of rearing juvenile pikeperch, Sander lucioperca (L.), in recirculating aquaculture systems

The aim of the study was to determine the impact of different light intensities on the results of rearing juvenile pikeperch, Sander lucioperca (L.), in recirculating aquaculture systems (RAS). In experiment I, the light intensities applied were 45.1 lx (group LI) and 385.7 lx (group HI) (initial body weight - 6.1 g), while in experiment II they were 1.2 lx (group LII) and 8.0 lx (group HII) (initial body weight - 42.2 g). In both experiments, the fish reared in the tanks with lower light intensity (groups LI and LII) exhibited faster growth rates (P < 0.05). In experiment I significant differences were also noted among groups with regard to feed conversion ratio (FCR) and protein efficiency ratio (PER). Fish mortality in both experiments was low, and differences among groups were not significant (P > 0.05). The results obtained indicate that the application of low intensity light (< 45 lx) during juvenile pikeperch (body weight > 6 g) rearing is justified since it has a positive impact on the behavior and growth rate of the fish, and the feed conversion ratio, which implies that it is possible to shorten the rearing period of this species.