Bivalve aquaculture is often promoted as low-impact, but uncertainty about mollusc sentience means welfare considerations cannot be entirely dismissed.
Bivalve welfare sits at the edge of current scientific and philosophical understanding. The evidence for sentience — subjective experience of pain — is weak compared to vertebrates, but the uncertainty is genuine rather than simply absence of evidence. Some animal welfare philosophers argue that under uncertainty we should extend precautionary consideration. Practically, the most commonly discussed welfare improvements involve rapid thermal killing rather than live consumption. Bivalve farming is nevertheless considered by many environmentally-conscious consumers as the most ethical form of animal-sourced protein available.