Environmental enrichment in aquaculture: linking welfare goals to practical applications

Aquaculture is the fastest growing food production sector globally, comprising freshwater and marine species reared under highly variable farming contexts, ranging from extensive earthen ponds to intensive recirculating and sea-based systems. Together with growth, production has also intensified, and the welfare of fish farmed in these systems has thus gained increased recognition as an essential contributor to sustainability of aquaculture. Environmental enrichment has emerged as a promising welfare management tool to improve fish welfare and deliver potential production benefits by promoting species-appropriate behaviour and reducing chronic stress; however, its effective implementation remains highly context dependent. This review synthesises current knowledge on environmental enrichment across five categories: Physical, Sensory, Dietary, Occupational, and Social, to evaluate their potential to produce measurable changes in physiological and behavioural indicators of welfare. Enrichment strategies are further assessed for their practicality and feasibility, identifying areas where enrichment is already integrated into aquaculture and where further innovation is required. To guide implementation, a goal-oriented framework is proposed that outlines a stepwise process for aligning welfare objectives with appropriate enrichment strategies while considering species, system, and operational contexts. This combined approach reframes environmental enrichment from a peripheral addition to an integrated component of welfare management in aquaculture.