European sea bass (Dicentrarchus labrax) is one of the most commercially important fish species in Mediterranean aquaculture, yet intensive farming conditions expose them to crowding stress, poor water quality, and handling trauma that compromise their welfare.
Research on sea bass sentience confirms they possess nociceptors, mount stress responses indistinguishable from those of mammals, and alter behaviour following painful stimuli. Chronic crowding suppresses immune function, increases aggression and injury rates, and is associated with abnormal swimming patterns and reduced feeding motivation. Welfare-conscious farms reduce stocking density below 15 kg/m3, implement water recirculation to maintain oxygen and remove waste, and use anaesthesia during handling procedures including grading and vaccination. Pre-slaughter crowding is a key welfare risk requiring attention.