Sea urchin aquaculture is growing as wild populations decline from overfishing. As echinoderms with a distributed nervous system, their sentience status and welfare needs deserve consideration.
Sea urchin welfare science is extremely limited. Given their very different nervous system architecture from vertebrates, assessing their capacity for suffering is challenging. However, their demonstrated nociceptive responses and behavioural modifications in response to damage suggest some form of aversive experience may occur. At the scale of sea urchin farming - millions of individuals - even small probabilities of suffering carry moral weight. Ensuring naturalistic feeding substrates and appropriate stocking densities represents a reasonable precautionary welfare measure.