Routine aquaculture procedures including vaccination, sorting, and sampling cause pain and stress in fish; anaesthesia substantially reduces these welfare harms.
The omission of anaesthesia and analgesia in routine aquaculture procedures is one of the most pervasive welfare problems in the fish farming industry. Vaccination, sorting by size, sampling, and treatment involve repeated capture and handling of individual fish, often without any form of pain or stress mitigation. Given that fish are now widely recognized as sentient animals capable of experiencing pain, this represents a major ethical gap. The cost and logistics of anaesthesia for large-scale operations are genuine challenges, but welfare-conscious producers have demonstrated that anaesthesia-first approaches are commercially viable.