How stocking density in trout aquaculture affects fish welfare and what better farming practices look like for salmonids.
Trout welfare in aquaculture has received increasing scientific attention as evidence for fish sentience has grown stronger. Trout demonstrate clear aversion to painful stimuli, show physiological stress responses to overcrowding, and can develop chronic stress-related conditions when housed at high densities. Yet many commercial operations maintain densities well above what would be considered acceptable if the animals involved were mammals. Improving stocking density standards, water quality management, and handling practices in trout farming represents a meaningful and achievable welfare improvement for billions of fish.