Influence of shy and bold zebrafish personalities on colonization and olfactory responses in sertraline-contaminated environments

Selective serotonin reuptake inhibitors (SSRIs) such as sertraline are used as antidepressants to treat mental disorders such as depression by blocking serotonin reuptake and thus maintaining high serotonin levels. Currently, increased consumption has led to detection of SSRIs in aquatic systems; however, information about their effects on exposed organisms is limited. This study investigated differences in the colonization response by zebrafish (Danio rerio) to sertraline-contaminated environments considering personality traits (shy and bold). Colonization was assessed in terms of success, efficiency, and inhabited time for each sertraline concentration. Fish were tested individually and in groups. In addition, whether these personality traits differed from each other in their olfactory sensitivity to different olfactory stimuli was studied, including sertraline, using the electro-olfactogram (EOG). Bold fish exposed in groups tended to colonize higher concentrations of sertraline than shy fish. These differences were not as significant when fish were exposed individually. Furthermore, analyses in the EOG detected that bold fish reacted between 1.3 and 2.8 times more to all stimuli studied. In contrast, sertraline was not detected by the olfactory system. Varied D. rerio colonization responses to sertraline-contaminated environments reveal specific personality-based vulnerabilities. These findings underscore the importance of integrating behavioral phenotypes into environmental risk assessments for pharmaceuticals.