Atlantic salmon in sea cage aquaculture show numerous behavioral indicators of chronic stress, with welfare research revealing the gap between their natural behavioral repertoire and what intensive production allows.
Atlantic salmon in sea cages exist in a fundamentally unnatural situation that prevents their natural behavioral repertoire. Their migratory drive has no outlet - they circle endlessly in nets that span a tiny fraction of their natural range. Aggression among conspecifics competing for space and feeding opportunities causes fin and scale damage that creates wounds and potential infection sites. The various treatment regimes required to manage sea lice - including pesticide baths, thermal treatments, and biological controls - impose additional acute stressors on fish that are already chronically stressed by crowding. Research using salmon behavioral indicators, including escape attempts and reduced feeding during stressful events, confirms that these fish experience and respond to aversive conditions.