Supplementary Data: Sustainability of salmon aquaculture systems and inclusion of local feed ingredients

The supplementary data provide detailed information on assumptions, experimental design, and supporting calculations underlying the life cycle assessment (LCA) of canola meal (CM) inclusion in Atlantic salmon feeds across cage and recirculating aquaculture systems (RAS). Section A outlines key system boundaries and assumptions, including excluded processes (e.g., infrastructure, packaging), zero volatilization of NH₃ and N₂O in RAS systems, fuel use modelling in SimaPro®, average transport distances for ingredients and feeds, and electricity mix adapted to New Brunswick, Canada. Transportation logistics for canola meal from Saskatchewan to the East Coast were modelled using rail over a 4,000 km distance.

Section B compiles all LCA input/output values. Section C details a feeding trial on post-smolt Atlantic salmon, evaluating growth performance and feed conversion across four experimental diets with increasing CM inclusion (0–15%). The trial used 12 tanks (1,200 L each), under controlled conditions (12.9 °C, 25 ppt salinity, 16L:8D photoperiod) over 103 days. No significant effects (P ≥ 0.05) were observed on feed intake or conversion ratio at CM inclusion up to 10%, confirming CM’s suitability at moderate levels.

Section D describes the modelling approach for nitrogen (N) and phosphorus (P) fate across the production systems. Section E presents the results of a Monte Carlo uncertainty analysis conducted on four production scenarios (cage and RAS with and without 10% CM inclusion), reporting key metrics such as standard deviation, coefficient of variation, and standard error for each environmental impact category. These supplementary materials ensure transparency and reproducibility of the LCA modelling and support the robustness of the environmental findings.