Exploring the relationship between stress coping styles and sex, origin and reproductive success, in Senegalese sole (Solea senegalensis) breeders in captivity

Individual animals commonly adopt different stress coping styles that have been shown to impact reproductive success and differ between sexes (female/male) and origin (wild/hatchery). Hatchery reared Senegalese sole (Solea senegalensis) exhibit a behavioural reproductive dysfunction and a complete failure to spawn viable eggs. Hence, the present study examined whether 1) reproductive success of Senegalese sole was linked to coping styles and 2) behavioural differences exist in relation to sex or origin. A total of 198 breeders held in two research institutions were submitted to three individual tests (restraining, new environment and confinement) and one grouping test (risk taking). In addition, a blood sample to quantify cortisol, glucose and lactate levels was obtained from each individual after completing the individual tests. Senegalese sole breeders showed individual differences in behaviour across the different behavioural tests that were consistent with proactive and reactive coping styles traits. However, the most striking result was that reproductive success, sex and origin of Senegalese sole was not biased to any specific coping style. Indeed, the behavioural responses were similar and consistent between fish grouped by reproductive success, sex and origin. This study presented information that contrasts with different studies on dominant aggressive species and indicated that social non-aggressive species such as Senegalese sole follow a cooperative strategy that favours equal opportunities between stress coping styles and sexes. Therefore, results suggest that maintaining both coping styles strategies are fundamental for a sustainable breeder population approach.