Stocking density, growth and growth variation in juvenile turbot, Scophthalmus maximus (Rafinesque)

Although high stocking densities of turbot have been achieved in culture using supplementary oxygenation, this rearing strategy ignores the possibility that high densities may interfere with behavioural interactions between individuals and thereby affect biomass gain. This study describes the effect of stocking density on the growth of juvenile turbot populations. Groups of juvenile turbot were reared at four different densities (initial densities: 0.7, 1.1, 1.5 and 1.8 kg/m 2) for 45 days. Treatment density had a significant effect on turbot growth rates over the experimental period. Fish held at the highest density showed lower growth rates and mean weights at the conclusion of the study than fish held at lower densities. The dispersion in fish weights was also affected by stocking density. The variation in fish weights was greatest in the highest density group and as stocking densities increased the growth of some individuals was suppressed. It is concluded that growth of juvenile turbot can be significantly increased and more homogeneous weights achieved by stocking the fish at lower densities than previously reported.