A Comprehensive Review of the Factors Influencing the Environmental Impact of different Species bred in Closed Land-based Recirculating Aquaculture Systems

Abstract: Today the future supply of seafood is threatened due to human activities which, among other things, has led to overfishing. However, more environmental friendly initiatives of producing seafood have emerged, such as Recirculating Aquaculture Systems (RASs). By analyzing the sensitivity analysis from six different Life Cycle Analysis (LCAs) on RASs, eight different factors that influence the environmental impact from RASs could be identified. These factors are; 1) By-products used, 2) Renewable electricity, 3) Global/local electricity mix, 4) Higher stocking density, 5) Nutrients emitted, 6) Crop-based feed, 7) Excluding land use change, 8) Feed conversion ratio (FCR) closer to 1. Whether the influence of each factor depended on the species being reared could not be determined, due to a large variation in the amount of factors addressed in each LCA. Renewable electricity was used as a factor in five LCAs and all five agreed that the use of renewable electricity reduced the environmental impact from fish reared in RAS. The variation in magnitude of these reductions could be explained by the location of each facility. Thus, the living conditions that each species require could not be determined as the cause of this variation. Crop-based feed did not lessen the environmental impact in all cases. The use of soybean meal increased the environmental impact when it was substituting krill meal. Further developments of LCA are needed to determine if the factors influence differ between different species.