All-male tilapia production reduces reproductive competition that would otherwise cause welfare problems in mixed-sex populations in intensive culture.
In mixed-sex tilapia populations, reproductive competition causes elevated aggression among males, territorial disputes, and energetic costs of courtship behaviour that reduce welfare. Uncontrolled reproduction creates overcrowding that reduces oxygen, increases ammonia, and degrades welfare for the entire population. All-male production, whether through hormonal sex reversal or genetic YY technology, prevents this reproductive chaos and its welfare consequences. The welfare benefit of preventing reproductive competition in intensive culture is substantial, though the welfare implications of the sex determination process itself require separate assessment.