Polychaete worms are enormously abundant marine invertebrates that form a critical part of seafloor food chains. Their use in aquaculture feed and research raises welfare questions at the edge of invertebrate consideration.
Polychaete welfare sits at the outer edge of meaningful consideration. Their nervous systems are relatively simple, but nociceptive responses and behavioural avoidance have been documented in some species. Bait digging removes millions of ragworms and lugworms from intertidal sediments annually with no welfare consideration. Their importance as prey for shorebirds and flatfish means that population-level welfare through sustainable harvest indirectly benefits many sentient species that depend on them.