Life cycle assessment of seabass and meagre in marine cage farming - From feeding plant to harvesting

Aquaculture is related to environmental impacts, both locally and globally. The purpose of this study was to identify environmental hotspots linked to fish feeds of various granulations, in seabass and meagre farming using Life Cycle Assessment (LCA) approach, given that recent studies suggest that fish feed is the predominant factor affecting marine fish farming. This, in turn, enabled a detailed comparison of environmental performance throughout the rearing cycle, in both species. LCA was applied to the production process of fish feeds taking into account the quantities of raw materials, heat and energy needed for the production of feed. Similarly, LCA was applied to cage farms in Greece, involving the quantity of feed per size class, energy and fuel needed for the production of one tonne of seabass and meagre, respectively. The smaller sized feed (SSF) class distributed to the fry, performed better compared to the medium (MSF) and large sized feed (LSF) classes fed to juveniles/adults, in relation to various environmental impact indicators. In medium and large sized feeds, the main negative contributor was the use of sunflower meal, while small sized feed affected these indicators through higher electricity demands and the quantity of fishmeal. A comparison between seabass and meagre revealed that meagre had a significantly lower impact on all eighteen environmental impact indicators. This should be attributed to reduced feed conversion ratio and lower fry requirements compared to seabass. Improvements in cultivation methods of raw materials, optimized reductions of raw materials of marine origin and improved feeding management could contribute to overall ecological sustainability of the sector.