Animal Welfare Research Needs for Farmed Salmonids

Following is a list of research priorities gaps identified during the farmed salmonids Code development process. Click here to visit the farmed salmonids Code web page for the Scientific Committee report and to view the full Code.

Rearing units

  • Safe and effective ozone and associated oxidants in saltwater recirculating aquaculture systems
  • Effect of the spectral composition of light on the welfare of salmonids at different life stages
  • Effects of different light intensities and photoperiods (compared with 24-hour constant light) on salmonid welfare at all life stages
  • Behavioural studies of salmonid preferences for and responses to different biodensities
  • What types of enrichments contribute to positive welfare and how can these enrichments be implemented and evaluated at different life stages?

Feeding management

  • The point at which feed withdrawal becomes a welfare issue caused by negative metabolic states
  • Viable alternatives to long feed withdrawal during depuration

Sea Lice

  • Sub-lethal effects of sea lice infestation (e.g., mechanical irritation, osmotic imbalances, disease transfer)
  • Methods to reduce injuries and other welfare issues associated with mechanical sea lice barriers and other lice removal technologies
  • Health and welfare impacts of repeated chemical and non-chemical sea lice control methods, and the use of multiple treatment modalities simultaneously
  • Impact of environmental changes (e.g., temperature, oxygen, salinity) on the health and welfare of salmonids undergoing sea lice treatment
  • Selective breeding for sea lice resistance


  • Strategies to improve environmental resilience of triploid fish
  • Origins and mechanisms behind observed increased rates of deformity in post-smolt triploid fish
  • Use of fish scale or water samples to estimate cortisol levels as a measure of stress
  • Welfare implications of identification methods (e.g., tagging, fin clipping) and possible approaches to pain control
  • Emergency euthanasia methods (e.g., during transportation)