Atlantic halibut hatchery production is challenging, with high mortality and welfare problems in juvenile stages. Improving early rearing conditions is key to sustainable aquaculture.
Juvenile halibut experience multiple welfare insults during early rearing: suboptimal lighting causing incomplete eye migration, inappropriate substrate denying settlement behaviour, and abrupt diet transitions. Providing dark resting periods, gravel substrate, and gradual diet weaning significantly reduces malformation rates and stress indicators. Species-appropriate rearing protocols are essential.