Effect of residence and size asymmetries upon the agonistic interactions between juvenile white-seabream (Diplodus sargus cadenati de la Paz, Bauchot and Daget, 1974)

Abstract

The behavioural patterns of juvenile white‐seabream suggest that asymmetry in residence is an important factor governing the outcome of contest between individuals of this species. Asymmetries due to resident status had strong effects on agonistic behaviour, with asymmetries in body sizes producing weaker effects. Resident fish won all the combats against intruders of lower or similar length. However, when the intruder was larger than the residents (higher than 5% in length and 20% in weight), the percentage of combats won by the residents decreased to 85.7%. There was a significant correlation between fight intensity and size asymmetry in favour of the resident fish. The resident fish was more aggressive and persistent in attacks, and contests were more intense when the size of the intruder was greater. During agonistic interactions, the frontal attacks and lateral displays were more frequent when the intruders were similar or larger than residents. Attacks to the flanks and chases were more frequent in pairs where the intruders were smaller. Aggr. Behav. 25:297–303, 1999. © 1999 Wiley‐Liss, Inc.

Dietary l-tryptophan alters aggression in juvenile matrinxã Brycon amazonicus

“…In a previous study on rainbow trout (Oncorhynchus mykiss), the winner fish presented higher locomotor activity and aggressive behavior, while the loser presented lower activity and were often prevented from feeding by the dominant fish (Pottinger and Carrick 2001). The aggressive behavior of the resident seems to represent an attempt to defend the invaded territory and was also described in brown trout (Salmo trutta) (Sundström et al 2003) and white seabream (Diplodus sargus cadenati) (Caballero and Castro 1999).…”

“…This escort activity was often characterized by a ''circling'' movement, in which the fish swims in circles, one following the other. This behavior has been described in Diplodus sargus cadenati, characterized as swimming in circles with the dorsal fin extended and the body shaking (Caballero and Castro 1999). During active chases and biting episodes, the matrinxã intruder remained in the corners of the aquarium, mainly at the surface but sometimes at the bottom, while the resident fish remained mostly in the middle of the aquarium.…”

Effect of competitor density on the aggressiveness of juvenile white seabream (Diplodus sargus cadenati de la Paz, Bauchot and Daget, 1974)

“…So, it could be expected that the strategy of resource defense against the number of intruders show an ''obvious'' lower threshold of aggressiveness, owing to the absence of competitors, and an upper threshold determined by loss of profitability (i.e., a rate lower than one in the relationship resource obtained/cost of defense [benefits/costs] [Grant, 1993]). The fixation of this upper threshold presents a major difficulty and does not always seem to be clearly evaluated by the resident [Caballero and Castro, 1999].…”

“…Otherwise, the upper and lower thresholds of aggressive defense of the resource proportionate to the density of competitors seem not only to be profitability criteria dependent but also to depend heavily on the resident's ability to fight. Fighting abilities are determined by different factors, the most significant of which are fish size [Enquist et al, 1987] and the motivation to fight (the value of the resource) [Caballero and Castro, 1999]. The lower thresholds observed in each trial indicate the existence of significant differences that can be ascribed to each resident.…”

The future of stock enhancements: lessons for hatchery practice from conservation biology

“…1986). However, prior residency conveys an advantage to the resident during aggressive interactions (Caballero and Castro 1999; Volpe et al . 2001), possibly accounting for the lack of evidence that displacement actually occurs in the wild (Deverill et al .…”