Dominance structure in small groups of juvenile white-seabream (Diplodus sargus cadenati de la paz, Bauchot and Daget 1974)

Abstract

Experiments were conducted to investigate the intraspecific aggressive interactions between juveniles of white‐seabream (Diplodus sargus cadenati de la Paz, Bauchot and Daget 1974) in relation to dominance hierarchy in small groups. The agonistic interactions between juvenile white‐seabream in small groups originated a peck‐dominance hierarchy. The dominant (α‐fish) generally interacted aggressively and most frequently with the subordinate that was next in line (β‐fish) within the dominance hierarchy. This β‐fish interacted aggressively more frequently with the γ‐fish, and so on. Results demonstrated that fish do not attack subordinates at random. The level of subordination in small groups of juvenile white‐seabream was related to body size. Generally, the more aggressive fish manifest a higher growth rate. Aggr. Behav. 24: 197–204, 1998. © 1998 Wiley‐Liss, Inc.

Dominance and growth of Diplodus sargus (Pisces: Sparidae) in small captive groups

“…The growth performance values of white seabream show an improvement of fish's size and condition along the 6 weeks of study (Table 1). Castro and Caballero (1998) found hierarchies in which fish carried out more attacks on the individual whose subordination level is immediately inferior to their own. In the present study, that finding was corroborated but several other features of the social hierarchies could be identified and characterized quantitatively, namely the predominance of linear structures, the level of stability from week to week and the clear relationship between the number of attacks initiated by a fish and its position in the group.…”

“…In this scenario, winners are predicted to gain advantages over losers in survival, growth or breeding success (Harwood et al, 2003). The study of Castro and Caballero (1998) showed a peckdominance hierarchy in groups of four white seabream. Our study gives a more detailed analysis of the structure of dominance orders in captive groups of six white seabream assessing the linearity and stability of such hierarchies.…”

“…In many cases, this slow growth reduces the profitability of commercial production (D'Anna et al, 2004). D. sargus displace very high levels of aggression in captivity (Caballero and CastroHdez, 2003;Castro and Caballero, 1998;Karakatsouli et al, 2007), and several authors raise the hypothesis of the slowing of growth being caused by an excess of behaviors related to aggression and escape (Caballero and CastroHdez, 2003;Karakatsouli et al, 2007;Papoutsoglou et al, 2006). This link is far from being proved, as several other factors may also reduce growth.…”

“…Previous studies on the aggressive behavior of D. sargus in aquaria (Castro and Caballero, 1998;Caballero and Castro-Hdez, 2003) showed that, in small captive groups, dominance hierarchies tended to develop generating asymmetries among group members. According to Castro and Caballero (1998), one or a few individuals win most contests while others become chronic losers.…”

“…According to Castro and Caballero (1998), one or a few individuals win most contests while others become chronic losers.…”