Oyster hatcheries produce larvae and juvenile spat for grow-out operations, with welfare considerations at larval stages reflecting the broader uncertainty about bivalve sentience.
The welfare status of oyster larvae is uncertain given their simple nervous system organization. However, hatchery production of oyster larvae has significant indirect welfare benefits for marine ecosystems by reducing wild oyster collection pressure. Water quality management in hatcheries prevents mass mortality events that represent welfare concerns under precautionary principles. OsHV-1 infection causes tissue damage and death in larvae that may involve aversive experience. Temperature and salinity management within optimal ranges prevents physiological stress. The development of disease-resistant Pacific oyster strains through selective breeding reduces disease-related welfare events. Hatchery production supports restoration of native oyster reefs that benefit diverse sentient marine species.