THE INFLUENCE OF FOOD DISTRIBUTION ON THE AGGRESSIVE-BEHAVIOR OF JUVENILE WHITE-SEABREAM (DIPLODUS-SARGUS CADENATI DE LA-PAZ, BAUCHOT AND DAGET, 1974)

Experiments were conducted to investigate the effect of differences in the spatial distribution of food on the aggressive behaviour of juven ile white-seabream, Diplodus sargus cadenati; both in the presence and in the absence of food. The groups of fish receiving spatially fixed food displayed less aggression than those receiving spatially variable food. The period (before, during, or after feeding) during which aggr essiveness is, measured also has influence in the results. During the prefeeding and postfeeding periods (absence of food), groups that were fed with food spatially fixed displayed less aggression than those th at received spatially variable food. However, when food was present th ere were no differences in the number of aggressive acts carried out b y fish groups in both environments. The aggressiveness shown by the gr oups of fish was always more pronounced during the postfeeding period than during the prefeeding period. The dominant fish was more aggressi ve when food was spatially fixed, and especially when food was present . Therefore, the subordinates were more aggressive when food was spati ally variable and particularly when food was present and during the po stfeeding period. (C) 1998 Wiley-Liss, Inc.