Environmental assessment of seabass (Dicentrarchus labrax) and seabream (Sparus aurata) farming from a life cycle perspective: A case study of a Tunisian aquaculture farm

Life Cycle Assessment (LCA) was applied to assess potential environmental impacts generated by production of 1 ton of European seabass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) on a sea-cage aquaculture farm in Tunisia. The studied farm produces 2100 tons of fish per year. Impact categories included in the current study were acidification, eutrophication, global warming, land occupation, total cumulative energy demand and Net Primary Production Use (NPPuse). In addition, a refinement of “sea use” impact category was proposed to assess impacts of aquaculture on the area of sea required and seabed degradation. Calculations were performed using the software SimaPro® 8.0, and the database ecoinvent 3.0 was used for background data. Uncertainty analysis was performed using Monte-Carlo simulations. Results of this study indicate that seabass rearing has lower mean impact than seabream rearing for all the impact categories considered. However, no significant differences were observed in all the impact categories except the global warming. Fish feed is the main contributor to most of the impacts studied, which is directly related to production of fish meal and oil as feed ingredients and the large amounts of nitrogen and phosphorus released into the environment. Management decisions aiming to optimize production and use of fish feed may have a positive impact on the environmental performance of the farm. It is essential to optimize diet formulation and to follow better feeding strategies and farming practices (e.g. stock management, feed distribution, accurate ration calculation) to lower feed-conversion ratios and consequently improve the environmental performance of aquaculture farms. LCA is a valuable tool for assessing decisions for improving environmental sustainability of aquaculture because it performs overall impact assessment and helps identify main areas for improvement.