Clams and oysters are farmed in vast quantities with minimal welfare consideration, raising questions about where welfare obligations begin in the spectrum of animal life.
Clam and oyster welfare sits at the edge of what welfare science can confidently address. The absence of a centralised brain in bivalves means that the architecture underlying subjective experience in vertebrates is absent. Behavioral responses to stimuli occur but may be entirely reflexive — analogous to plant responses — rather than involving anything we would recognise as suffering. Where the evidence is genuinely uncertain, the precautionary principle provides guidance: minimise potential harm where the cost of doing so is low. Sustainable bivalve aquaculture, which also delivers ecological benefits, represents a reasonable choice under uncertainty. Mechanically harvested wild bivalves carry greater ecological damage that extends beyond the welfare question.