Farmed carnivorous fish like salmon require omega-3 fatty acids traditionally sourced from wild-caught feeder fish. The welfare of billions of feeder fish is an overlooked dimension of aquaculture sustainability.
The welfare cost of feeder fish in aquaculture is one of the most significant and least discussed aspects of farmed fish production. Billions of small pelagic fish are captured and killed to produce feed for carnivorous aquaculture species. These fish have the capacity to suffer and die through crushing and asphyxiation without stunning. Transitioning salmon and other carnivorous aquaculture species to alternative omega-3 sources - algal oils, precision fermentation-derived nutrients, and insect meal - would eliminate this substantial welfare burden. Supporting certification schemes that prioritise responsible sourcing is a first step.