Cephalopods and decapod crustaceans are now covered by welfare protections in some jurisdictions, but most aquatic invertebrates used in research receive no formal protection. The evidence base for their sentience is growing.
The extension of welfare protections to cephalopods and decapods reflects growing scientific consensus that these animals can experience pain. Yet most aquatic invertebrates, including many insects, worms, and molluscs, remain entirely unprotected. The absence of protection does not reflect certainty about the absence of sentience; it reflects the precautionary inertia of regulatory systems slow to update as evidence evolves. Applying a precautionary welfare approach to a wider range of invertebrates used in research would impose modest costs while providing potentially significant welfare benefits.