Fish welfare in aquaculture: Status, challenges, and future directions

The rapid expansion of aquaculture to meet global protein demand underscores the critical need to prioritize fish welfare within sustainable production frameworks. Grounded in a review of contemporary scientific literature, industry reports, and policy documents (1992-2026), this paper provides a perspective-informed, systems-oriented synthesis of fish welfare in aquaculture, with clear relevance for policy development. Moving beyond the traditional "Five Freedoms," we adopt an evolving welfare perspective that emphasizes a "life worth living," acknowledging fish sentience and their capacity for pain and stress. Our analysis identifies significant regional disparities in welfare implementation, from advanced oversight in research to inconsistent and often unregulated practices in major producing nations. Key challenges persist across stocking density, water quality, slaughter methods, disease management, and early life-stage care. Conversely, emerging technologies, such as AI-driven behavioural monitoring, real-time sensors, and precision systems, present transformative opportunities for proactive welfare management. We argue that the future of ethical and sustainable aquaculture depends on three interconnected pillars: (1) the development and adoption of mandatory, species-specific welfare guidelines implemented through a practical tiered regulatory model to ensure global relevance and phased compliance; (2) the strategic integration of cost-effective technologies for scalable welfare assessment and improvement; and (3) the strengthening of ethical oversight frameworks, drawing principles from research ethics (e.g., IACUC) to inform commercial practices. Ultimately, aligning economic viability with robust welfare standards is essential to secure the industry's social license, enhance productivity, and meet growing consumer demand for humanely produced seafood.