UTTAR PRADESH JOURNAL OF ZOOLOGY

Global aquaculture has expanded considerably over recent decades, now supplying more than half of the world's seafood for direct human consumption. Despite its recognised contribution to food security and nutrition, the sector generates greenhouse gas (GHG) emissions through diverse pathways that include feed production, energy consumption, land-use change, and direct gaseous emissions from production systems. Life cycle assessment (LCA) has become the principal methodological framework for quantifying the carbon footprints of farmed seafood, yet its application across different species, production systems, and geographic contexts remains highly heterogeneous, complicating cross-study comparisons and the formulation of targeted policy responses. This review critically examines the state of knowledge on carbon footprints in aquaculture, with particular attention to methodological advances in LCA, comparative emissions across production systems, and promising strategies for emission reduction. The evidence indicates that carbon footprints vary enormously across species and systems — from less than 1 kg CO₂-equivalent per kilogram of live-weight product for filter-feeding bivalves and certain seaweed species, to well over 20 kg CO₂-eq kg⁻¹ for intensively produced carnivorous species. Feed production, particularly the harvesting and processing of wild fish for fishmeal and fish oil, consistently emerges as the dominant emission hotspot in fed aquaculture. Advances in LCA methodology, including the adoption of consequential approaches, enhanced allocation procedures, and integration with biodiversity and water-use impact categories, are improving the analytical rigour and policy relevance of carbon accounting in the sector. Mitigation strategies such as alternative protein feeds, renewable energy uptake, recirculating aquaculture systems, and integrated multi-trophic aquaculture offer credible pathways toward decarbonisation, though their effective deployment requires supportive governance frameworks and sustained investment in infrastructure and monitoring capacity.