Farming carnivorous fish like salmon requires large quantities of wild fish as feed. The welfare implications for the billions of wild fish harvested as aquafeed is a largely overlooked issue.
The welfare implications of aquafeed production represent an often-invisible welfare problem embedded in farmed fish production. For every kilogram of farmed salmon produced, multiple kilograms of wild-caught pelagic fish — themselves likely sentient — were captured, crowded, and killed without stunning. Industrial fishing methods that harvest billions of small fish are not designed with welfare in mind: capture by trawl, crowding in nets, and processing while alive or shortly after death create welfare costs at astronomical scale. The development of alternative protein sources for aquafeed — insect meal, algae, and fermentation-derived proteins — represents a welfare improvement opportunity for both the farmed fish (potential health benefits from diverse diets) and the wild fish populations currently harvested as feed.