RESPONSE TO COLORS IN DICENTRARCHUS-LABRA X (MORONIDAE), IN A SELF-FEEDING AND MULTIPLE-CHOICE CONDITION

A population of sea-bass, housed under semi-natural and self-feeding c onditions, was presented with six different coloured levers. Their cho ices tended to favour more colour-contrasted levers and were greatly a ffected by environmental conditions such as stress factors, circadian period. season, and thermal fluctuations. A correlation was observed b etween increases in instrumental acitivity, indicating an increase in energetic requirements, and a widening of choices in the exploitation of the coloured levers. Consequences of these behaviours were consider ed in relation to predator pressure that the fish imposes on potential prey populations in the natural environment, and in relation to the i nitiation of feeding activity when the fish are maintained in captivit y and under self-feeding conditions.