Feeding and growth responses of sea bass (Dicentrarchus labrax) reared by four feeding methods

As they grew from approximately 2.8 to 260 g, sea bass were fed according t o four feeding methods: self- (SF), automatic (AF), hand (HF, two meals per day), and combined (CF, automatic and to satiation by hand) feeding. The e xperiment, which lasted 79 weeks, was conducted under ambient environmental conditions. Feed supply to SF and HF fish was similar (P > 0.05), except d uring the last period when an increased feed input was recorded in the SF g roup. The AF fish were always overfed. Hand-fed (HF) sea bass consumed 52-6 1% of their daily ration during the afternoon feeding. AF-fed juveniles did not grow well initially but weight gain was higher later, resulting in a s imilar mean individual weight to the other methods. The weight of adults wa s lowest in SF-fed fish (in AF and HF fish weight was significantly better) . Mortality (0.4-1.1%) occurred only amongst juveniles and was independent of feeding method. Juveniles fed according to the SF method had diurnal fee ding activity which changed progressively to increased nocturnal feeding, w ith a main peak of activity at mid-day and a secondary one around dawn or d usk. From an aquaculture viewpoint, SF has the advantages of good feed conv ersion and lower labour costs as compared to the other feeding methods. (C) 1999 Elsevier Science B.V. All rights reserved.