Bivalve molluscs like mussels and oysters are farmed in vast quantities — their capacity for sentience is scientifically uncertain, but the precautionary principle supports considering their welfare.
Bivalve welfare sits at the frontier of animal sentience research. The dominant scientific view holds that bivalves almost certainly lack the neural complexity for pain experience as vertebrates experience it. However, this judgment is probabilistic, not certain. Given the vast numbers farmed (trillions annually), even a small probability of sentience multiplied by that scale creates a non-trivial welfare consideration under the precautionary principle. Practically, the most welfare-defensible approach is rapid death methods (boiling or crushing) rather than slow desiccation. Bivalve farming is widely considered among the lowest animal welfare footprint food-production options available, making it a reasonable choice for consumers reducing animal product consumption while maintaining some seafood.