Response of captive seabass and seabream as behavioural indicator in aquaculture

Welfare of cultivate fish at high-density represents an important concern for modern aquaculture. The behaviour of European seabass (Dicentrarchus labrax) and seabream (Sparus aurata) reared in cages was studied in a fish farm of northern Sardinia (Italy) in autumn 2006 to test whether captive condition had an effect on the movement patterns of these two species. Video images recorded before, during and after the manual feeding distribution allowed us to collect data on different behaviours of captive fish. Thus, behaviours indicating the position of fish in the water column, swimming direction and possible aggressive behaviours (aggression, direction change and collision) showed juveniles and adults of seabass and seabream were overall affected by feeding rhythms and captive overcrowding. Seabream had a major tendency to swim towards the bottom and higher frequency of horizontal swimming and collisions than seabass. The overall behavioural difference between two species was explained in terms of their differences in ecological features in the wild.