Pharmaceutical pollution influences river-to-sea migration in Atlantic salmon (Salmo salar)

Abstract

Despite the growing threat of pharmaceutical pollution, we lack an understanding of whether and how such pollutants influence animal behavior in the wild. Using laboratory- and field-based experiments across multiple years in Atlantic salmon (Salmo salar; n = 730), we show that the globally detected anxiolytic pollutant clobazam accumulates in the brain of exposed fish and influences river-to-sea migration success. Clobazam exposure increased the speed with which fish passed through two hydropower dams along their migration route, resulting in more clobazam-exposed fish reaching the sea compared with controls. We argue that such effects may arise from altered shoaling behavior in fish exposed to clobazam. Drug-induced behavioral changes are expected to have wide-ranging consequences for the ecology and evolution of wild populations.

Published in

Science
2025, volume: 388, number: 6743, pages: 217-222

SLU Authors

• Brand, Jack

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • Zoological Society of London

• Michelangeli, Marcus

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • Griffith University

• Bose, Aneesh

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • Max Planck Institute of Animal Behavior

• Cerveny, Daniel

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • University of South Bohemia in České Budějovice

• Martin, Jake

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • Deakin University
  • Monash University
  • Stockholm University

• Hellström, Gustav

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    

• Mccallum, Erin

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    

• Holmgren, Annika

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    

• Thoré, Eli

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • University of Leuven (KU Leuven)
  • University of Namur

• Brodin, Tomas

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    

• Bertram, Michael

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • Monash University
  • Stockholm University

UKÄ Subject classification

Behavioral Sciences Biology
Environmental Sciences

Publication identifier

• DOI: https://doi.org/10.1126/science.adp7174

Permanent link to this page (URI)

https://res.slu.se/id/publ/141583