European sea bass are farmed at scale in Mediterranean countries. Understanding adult welfare in sea cage and land-based systems guides evidence-based improvement.
Adult sea bass welfare in floating sea cages is challenged by the interaction between species behavioral needs and commercial production requirements. Sea bass are naturally semi-pelagic fish that range over significant distances in schooling groups. The limited swimming volume of commercial sea cages — even large ones — restricts this behavioral ecology. Social hierarchies established within cages create chronic subordination stress for lower-ranking individuals.
Sea cage welfare is significantly affected by environmental conditions including temperature, oxygen, currents, and jellyfish intrusion. Mediterranean summer temperatures can exceed the comfort threshold for sea bass, causing heat stress and reduced immune function. Oxygen management during warm periods is welfare-critical — oxygen depletion events cause acute welfare harm and mortality.