Effect of feed pellet size and tank water level on growth performance in juvenile pikeperch, Sander lucioperca (L.), reared in a recirculating system
Three 28-day experiments were performed to assess the impact of two sinking feed pellet sizes (0.5–1.0 and 0.9–1.6 mm for experiment I, 0.9–1.6 and 1.3–2.0 mm for experiment II, and 1.3–2.0 and 1.6–2.4 mm for experiment III) and two tank water levels (0.50 and 0.65 m) on the growth performance of juvenile pikeperch of different mean initial body weights in experiment I, II, III respectively (1.1 ± 0.1 g, 5.1 ± 0.2 g, 16.6 ± 0.5 g) at different ages (67, 102, and 137 days post hatch). Two-factor analysis of variance showed that the growth of pikeperch was positively correlated with feed pellet size in experiment I, both feed pellet size and water level in experiment II, and water level in experiment III. The feed pellet sizes of 0.9–1.6 and 1.3–2.0 mm at body weights of 1.1 g and 5.1 g, respectively, are recommended to promote more efficient pikeperch growth rates. In the case of pikeperch with a body weight of 16.6 g, the feed pellet size was less important than the tank water level.