Anesthetic use in fish aquaculture reduces the welfare harm of handling procedures. Evidence-based protocols minimize stress during vaccination, grading, and health assessment.
Fish anesthesia represents an important welfare tool for reducing handling stress during necessary aquaculture procedures. Handling stress in unanesthetized fish causes cortisol elevation, physiological disruption, and injury risk that can be largely prevented with appropriate anesthetic protocols. The evidence for fish pain and stress experience supports treating repeated unanaesthetized handling in aquaculture as a significant and avoidable welfare burden. Vaccination programs in salmon aquaculture have led the way in adopting anesthetic protocols as standard practice. Extending anesthetic use to other handling procedures — grading, health assessment, and transport — represents a practical welfare improvement available with existing technology at relatively modest cost. Staff training in optimal anesthetic concentration and recovery monitoring is important for ensuring welfare benefits are achieved consistently.