The effects of ration level on feed intake and growth, and compensatory growth after restricted feeding, in turbot Scophthalmus maximus L.

Feed intake and growth were studied in groups of turbot fed daily rations o f 0.25%, 0.38% and 1% of body weight day(-1) for 41 days. Then, all groups were fed 1% of body weight day(-1) for the next 34 days. The two restricted rations resulted in reduced growth rates (30% and 60% of fully fed control s), and there was a tendency for increased growth heterogeneity (coefficien t of variation increased from about 100% to about 150%) compared with contr ols on full rations. Nevertheless, restricted rations did not result in any increase in size heterogeneity with the passage of time: the coefficient o f variation for weight changed little irrespective of feeding treatment. Th e turbot became hyperphagic and displayed compensatory growth after the cha nge from restricted to excess feeding, with compensatory growth being most marked among the fish that had been subject to the most severe feed restric tion. The results provided some evidence of increased variability in feedin g and growth within groups of turbot fed restricted rations, possibly as a result of the establishment of weak feeding hierarchies. When feeding restr ictions were lifted, the turbot that had reduced growth under feed restrict ion were able to completely compensate for lost growth.