Life-Cycle Assessment of Mariculture: Methodological Challenges and Priorities for Sustainable Blue Food Systems

Mariculture is expected to support sustainable food systems and coastal economies, yet its environmental performance varies markedly among production systems. Life-cycle assessment (LCA) links farm operations with upstream and downstream processes, but inconsistent functional units, system boundaries, allocation rules, impact categories, and ecological-process accounting limit cross-study comparison. This study presents a narrative synthesis of 83 studies identified through a systematic search of the Web of Science Core Collection and retained after structured relevance screening and full-text verification. The main findings are as follows: Fed finfish and shrimp systems were primarily influenced by feed supply chains, farm energy use, survival, and nutrient emissions. Bivalve and seaweed systems shifted attention toward hatcheries, infrastructure, vessels, yield, post-harvest handling, and carbon or nutrient accounting. Integrated systems and emerging technologies showed mitigation potential, but their benefits depended on uptake efficiency, electricity mixes, infrastructure lifetimes, and allocation choices. Overall, the evidence supports a transition from isolated product footprints toward transparent, regionalized, and prospective assessments. Future research should prioritize inventory transparency, regionalized impact assessment, nutrition-sensitive functional units, separate reporting of ecosystem services and conventional environmental burdens, and explicit boundaries for environmental claims.