Abstract
As aquaculture production has grown to meet rising demand for healthy seafood, the demand for aquaculture feed has increased substantially, placing greater pressure on finite marine ingredient resources. Periods of fish oil shortage, such as during the 2023–2024 El Niño, can reduce dietary levels of the essential omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), negatively affecting salmon farming performance. This large-scale observational study analyzed more than 430 million Atlantic salmon (556 generations) to quantify the relationship between dietary EPA+DHA levels and commercial production outcomes. Using population tracing and Inverse Probability Weighted Regression Adjustment, the study found positive responses for populations receiving higher dietary EPA+DHA levels (>9%TFA, total fatty acids). The positive responses included lower mortality (−8%), improved economic feed conversion ratio (eFCR; −13%), and higher harvest quality (+2%) compared with populations receiving lower levels (<7%TFA). Higher EPA+DHA levels were also associated with greater production predictability. Variability in mortality, eFCR, and harvest quality was reduced, with coefficients of variation declining by 50%, 27%, and 29%, respectively. These improvements narrowed the uncertainty associated with environmental stressors contributing to more consistent performance under commercial conditions. Scenario modelling assessed the impact of increasing dietary EPA+DHA from 6% to 10% using Veramaris ® algal oil. The resulting biological improvements reduced the carbon footprint and marine footprint of harvested salmon by 17% and 15%, respectively. These gains generated a positive return on investment through better survival, feed efficiency, and harvest quality. Overall, the results indicate that higher dietary EPA+DHA levels can improve the profitability, stability, and sustainability of commercial salmon aquaculture.