Bivalves like mussels and oysters have very simple nervous systems and are considered by most welfare scientists to have minimal sentience. Their farming may represent among the most ethical animal product choices.
Bivalve welfare occupies a unique position in animal welfare science — the weight of current evidence suggests that mussels and oysters are at the boundary of sentience or below it, with no clear evidence of subjective pain experience. Their farming consequently represents potentially one of the most welfare-acceptable forms of animal agriculture available. The environmental credentials of bivalve farming — no feed inputs, water filtration benefits, low carbon footprint — combined with the low probability of sentience make them a reasonable choice for people concerned about both animal welfare and environmental impacts. This assessment is provisional — welfare science should remain open to revision if new evidence emerges. Current evidence places bivalves well below the sentience threshold of fish, crustaceans, and certainly vertebrates.