Repeatability and personality differences between wild and captive-bred juveniles of gilthead seabream, Sparus aurata

Abstract

[eng] Animals differ consistently in several aspects of their behavior between members of the same species affecting many ecological and evolutionary processes. When these differences are consistent across time and ecological contexts, individuals reflect distinct personalities or behavioral types. Here, the behavioral variation in juvenile gilthead seabream, Sparus aurata, was quantified along five major axes of personality (exploration-avoidance, aggressiveness, sociability, shyness-boldness and activity) with standardized behavioral tests across two strains of fish (wild and captive-bred), to determine the possible origin of consistency in individual variability in marine fish and the effects of domestication on the behavior of this species. Continuous recording of fish in the behavioral arenas complemented with a developed software of automatically-tracking via Deep-learning algorithms, were carried out during the tests for automatic extraction of behavioral metrics. The variance of the five behavioral traits was using linear mixed models and we estimated repeatability scores (R) while controlling for environmental co-variates: fish strain, experimental trial and fish size. Between- and withinindividual variance decomposition revealed significant repeatability in all five behavior traits suggesting high predictability of individual behavioral variation across the different axes, and the existence of different personalities. In addition to the repeatability of the behavior of gilthead seabream, we found captive-bred fish to be more aggressive, social, active and more explorative then their wild congeneric individuals. The decomposition of the phenotypic variance into between- and within-individual correlations among behavioral traits revealed significant correlation at between-individual level for exploration-sociability, defining two behavioral syndromes in gilthead seabream. Our work provides the first basement of the repeatability scores of wild gilthead seabream and provide novel insight into the behavior of this important commercial species with implications for fisheries and aquaculture.