The effects of diet and stocking density on the growth and behaviour of pond pre-reared pikeperch under intensive conditions

摘要

Experiments were carried out between 1999 and 2001 on pikeperch fingerlings using two feeds at four stocking densities to evaluate the success of training 35-day-old pond-reared pikeperch, Stizostedion lucioperca L., to lifeless feed in intensive culture. Training periods of 28 days for each of three cohorts (1999-2001) were applied to introduce pikeperch from zooplankton to minced feed. In a preliminary study (1999), two feeds (live prey and minced fish meat) were compared at two stocking densities. Two higher densities were investigated in 2000 and 2001 and matched with the minced fish diet. Different feeds had significant effects on feed consumption and, as a consequence, on body weight gain; fish fed live prey showed highest growth rates. Unexpectedly, the stocking density had no significant effect on growth, and at the highest density there was a significantly betterfeed conversion rate. Stocking density and feed type significantly influenced the feeding behaviour. Three characteristic foraging techniques are described.