Summary: Gonçalves et al. (2012)

The white seabream Diplodus sargus is an economically important fish that shows high levels of aggression in captivity, making aquaculture difficult. In this study, Gonçalves et al. (2012) assessed growth rate and dominance hierarchies in seabream to test whether stable dominance orders can be established in captivity and whether dominance status affects rate of growth and body condition. They established 8 groups consisting of 6 individuals and measured the linearity of hierarchies every week, and the stability of these hierarchies on a week-to-week basis, for 6 weeks. They found that the dominance structures followed a linear pattern and were stable between weeks. However, there was no significant correlation between the dominance index and both growth rate and final body condition. They conclude that aggressive competition is not the primary cause in growth differences, although longer term effects induced by stress may be contributing factors.