The relationship between individual consumption and growth in juvenile turbot, Scophthalmus maximus

The development of feeding hierarchies was investigated in juvenile turbot, Scophthalmus maximus (Rafinesque) held at two rearing densities for 82 days. Individual biometrics were measured on five occasions and a diet labelled with ballotini glass beads was used in combination with a noninvasive radiographic technique to estimate consumption rates. The results demonstrate that the inclusion of the radio-opaque glass beads in the diet did not significantly reduce consumption by turbot. A significant relationship was found between individual consumption and growth of juvenile turbot. A weight differential within groups increased with time and was largely explained by inter-individual variation in food consumption. This differential was driven by an uneven distribution of food within groups, where individuals of a higher weight than the group average consistently consumed a greater than average share of the group meal, and showed less day to day variation in consumption than their smaller counterparts. The results demonstrate that in captive turbot groups, size hierarchies are mediated, at least in part, through inter-individual differences in food consumption.