Domino A. Joyce

Abstract Serotonin is involved in multiple diverse and complex biological processes. Selective serotonin reuptake inhibitors (SSRIs) are often used to test this, and fluoxetine, a commonly detected SSRI in aquatic ecosystems from pharmaceutical pollution, has been found to disrupt important behaviours and functions in organisms exposed to the antidepressant.

1 INTRODUCTION Fragmentation and loss of habitat caused by the conversion of land and waterways for human activities is a serious threat to Earth's biological diversity (Collinge, 1996; Jetz et al., 2007).

Abstract Fragmentation of watercourses poses a significant threat to biodiversity, particularly for migratory fish species. Mitigation measures such as fishways, have been increasingly implemented to restore river connectivity and support fish migration. The effects of such restoration efforts are typically tested using telemetry and fisheries methods, which do not fully capture the broader population movements that may have important consequences for population viability.