Dissolved oxygen management is fundamental to fish welfare in aquaculture, with hypoxic conditions causing significant distress and welfare compromise in affected fish.
Dissolved oxygen management is one of the most fundamental fish welfare parameters in aquaculture because inadequate oxygen is immediately and acutely distressing. Fish cannot hold their breath and cannot tolerate hypoxia even briefly without physiological stress. As oxygen levels fall below species-specific thresholds, fish experience the metabolic equivalent of suffocation - increased gill movement, reduced activity, surface crowding, and in severe cases mortality. The welfare problem is compounded by the non-linear relationship between temperature and oxygen solubility: warm summer temperatures both increase fish metabolism and reduce oxygen availability simultaneously. Continuous monitoring and automated supplementation represent the most reliable welfare management approach for oxygen in intensive aquaculture.