Economic values of growth, fillet yield, disease resistance and survival in organic rainbow trout (Oncorhynchus mykiss)

Summary

In aquaculture breeding programs, trait weights are often based on desired genetic gains rather than economic values (EVs), a practical approach when data are limited or when controlling correlated responses, but one that does not necessarily maximize economic returns. EVs quantify the profit change associated with a one‑unit genetic improvement in a trait and can be derived using profit equations or bio‑economic models, the latter being particularly suitable for complex production systems such as fish farms. Although bio‑economic modelling has been applied in rainbow trout, EVs have not yet been published for organic production systems, which differ from conventional systems in stocking density, veterinary restrictions, hormone prohibition, and feed requirements. This study estimated EVs for key traits—growth, fillet yield, feed conversion ratio, disease resistance, and survival—in Danish organic rainbow trout farming. Because organic systems are constrained by maximum allowable feed input linked to phosphorus and nitrate limits, two scenarios were evaluated: an unconstrained organic farm and one operating under annual feed limitations.