Bivalves including mussels, oysters, and clams occupy an uncertain position in animal welfare ethics; the evidence for their sentience and the welfare implications of harvesting warrant careful consideration.
Bivalve welfare sits at the frontier of animal welfare ethics. The precautionary approach — taking welfare considerations seriously even under uncertainty about sentience — suggests attending to the conditions in which bivalves are kept and killed, even if the moral weight assigned to any individual is low. More concretely, the ecological welfare implications of bivalve farming and harvesting — effects on seabed ecosystems, associated species bycatch, and habitat disturbance — are clearer than individual bivalve welfare. Hand harvesting and rope culture methods have significantly lower ecological and potential individual welfare impacts than dredging. For consumers seeking to minimise animal product harms, bivalves from low-impact production methods occupy an interesting position in the food ethics landscape.