Mussels and other bivalves occupy an uncertain position in welfare science, with their sentience debated and their farming practices recommended by some as a high-welfare protein source.
Bivalve welfare sits at the frontier of animal welfare science. The precautionary principle suggests that until sentience can be definitively excluded, some welfare consideration is appropriate. However, the probability of morally relevant suffering in mussels is considered by most welfare scientists to be very low. The farming practices — water filtering and substrate attachment — are relatively benign compared to the intensive conditions required for fish and crustaceans. Mussels represent one of the few animal protein sources where the welfare and environmental cases align: low impact, high protein yield, likely low sentience.