How dissolved oxygen, ammonia, temperature, and pH affect fish welfare in aquaculture systems, and management approaches.
Fish welfare is fundamentally dependent on water quality. Unlike terrestrial animals where environment quality is often visible, water quality problems are invisible until fish show behavioral signs of distress. Poor oxygen levels cause fish to surface for air in an aversive response. High ammonia causes gill damage and behavioral disruption. Temperature excursions cause stress and immune compromise. Many welfare problems in aquaculture trace back to inadequate water quality management, making environmental monitoring a core welfare requirement.