Valorization of Seafood Processing Byproducts for Sustainable Fertilization: Opportunities and Food Safety Considerations in Agriculture 4.0

The transition toward sustainable and circular bioeconomies in Agriculture 4.0 demands fertilization strategies that reduce environmental impacts while maintaining agronomic productivity. This article presents a structured narrative review of peer-reviewed literature integrating evidence across waste management, soil science, food safety, and regulatory frameworks to evaluate the potential of seafood processing byproducts including fish offal, shellfish residues, and aquaculture effluents as nutrient-rich fertilizers. These materials provide nitrogen, phosphorus, calcium, and essential micronutrients and may contribute to nutrient recycling within precision and resource-efficient agricultural systems. Evidence from diverse cropping contexts indicates that seafood waste-derived fertilizers can improve crop yield, nutrient use efficiency, and soil biological activity under site-specific conditions. Biological processing methods, including composting, enzymatic hydrolysis, and fermentation, are examined for their roles in enhancing nutrient bioavailability and reducing undesirable constituents. Particular emphasis is placed on food safety considerations, including heavy metals, persistent organic pollutants, antimicrobial resistance, pathogens, and microplastics, with discussion of speciation-based risk assessment and mitigation strategies such as thermal treatment, microbial screening, and compliance with international standards. Regulatory fragmentation, economic feasibility, and lifecycle environmental implications are also critically assessed. Emerging digital tools, including Internet of Things (IoT)-enabled nutrient monitoring and artificial intelligence (AI)-assisted compost optimization, are discussed as enabling technologies for integrating seafood-derived biofertilizers into smart farming systems. Overall, this interdisciplinary synthesis highlights the potential contribution of seafood waste valorization to circular nutrient management, environmental stewardship, and sustainable food production.