Water temperature is one of the most critical variables affecting farmed fish welfare, influencing physiology, behaviour, disease susceptibility and slaughter welfare outcomes.
Water temperature management is fundamental to farmed fish welfare in ways that have no direct parallel in terrestrial livestock farming. Fish cannot thermoregulate behaviourally beyond moving to cooler water depths, and in confined net pens with temperature stratification they may be unable to access appropriate temperatures. Prolonged exposure to temperatures outside the thermal preference range causes chronic physiological stress, immune suppression and cumulative suffering. As climate change intensifies temperature extremes, welfare and sustainability pressures are driving investment in closed containment systems with active temperature control as the more welfare-positive alternative to open-net pen aquaculture.