Procedure of collecting data and statistical
analyses. Measurements of fish individuals (body
weight, BW ± 0.1 g, total length, TL ± 0.1 cm) were
taken at the beginning of each experiment and at
two-week intervals throughout rearing. The fish
were anaesthetized in a 1.0 ml/l PROPISCIN (IFI
Olsztyn) solution (Kazuń and Siwicki, 2001). The
biomass of the fish in each tank was determined
weekly by weighing (±1.0 g) the entire stock in a
container with the known water volume. Collected
data were used to calculate:).