Life cycle assessment of a recirculatory aquaculture system (RAS) – A case study of meagre (Argyrosomus regius) farming

As global demand for seafood continues to rise, sustainable aquaculture plays a vital role in supplying high-quality food while reducing pressure on wild fish stocks and minimising their environmental impacts. Recirculating Aquaculture Systems (RAS) have emerged as a promising solution to overcome the negative impacts caused by other production systems, such as cages and ponds, offering controlled production environments with reduced water use and waste discharge. However, RAS also has environmental impacts that must be thoroughly assessed to ensure their viability as a sustainable alternative. This study applies Life Cycle Assessment (LCA) methodology to evaluate the environmental performance and identify potential improvements of a pilot-scale RAS farm of meagre ( Argyrosomus regius ) in Portugal. The environmental impact categories considered were global warming, freshwater eutrophication, marine eutrophication and land use. It was found that energy and feed production were the main contributors to most environmental categories, except for marine eutrophication, where the main contributors were oxygen and ozone system inputs. Main potential improvements include broader use of renewable energy in the system, use of more sustainable feed ingredients, such as the utilisation of by-products for fishmeal and fish oil ingredients, and relocating the hatchery to the grow-out farm which positively impacted all environmental categories by eliminating the need to transport juveniles. The insights gained from this study enhance the understanding of the environmental profile of RAS-based meagre farming and provide a foundation for improving environmental efficiency in future operations. • Energy use is the main contributor, accounting for 61% of global warming impacts. • Feed production significantly contributes to land use. • Renewable energy integration reduces GHG emissions by 42% in RAS operations. • Sustainable feed and on-site hatchery also offer key pathways to sustainability.