Estimating economic values in organic rainbow trout (Oncorhynchus mykiss) aquaculture using a bio-economic model. (original) (raw)

Verweij, Janneke Willemijn; Buitenhuis, Albert Johannes and Nielsen, Hanne Marie (2026) Estimating economic values in organic rainbow trout (Oncorhynchus mykiss) aquaculture using a bio-economic model.Aquaculture, xxx, xx-xx. [draft]

Summary

Economic values (EVs) enable optimisation of breeding goals, yet aquaculture breeding programmes often rely on desired gains rather than EVs. Bio-economic models offer an effective tool for deriving EVs in complex pro-duction systems, such as aquaculture systems, but their use in aquaculture remains limited and no EVs have been published for organic rainbow trout farming. Because organic aquaculture differs from conventional aquaculture in stocking density, restricted use of antibiotics and veterinary treatments, prohibition of hormone use, and organic feed requirements, EVs – particularly for disease resistance – may also differ. Resistance to rainbow trout fry syndrome (RTFS) is a relevant trait for a breeding goal, given the high mortality rates and moderate heritability. As EVs may change non-linearly with varying phenotypic levels of breeding goal traits, understanding this sensitivity is essential for developing economically optimal breeding goals. Therefore, this study (1) estimated EVs for production traits in an organic rainbow trout farm in Denmark; (2) quantified the sensitivity of EVs to different phenotypic levels of disease survival and overall survival; and (3) examined how different phenotypic levels of overall survival in-fluence the EV of RTFS survival, and vice versa. A bio-economic model was developed to simulate an organic rainbow trout farm operating under an annual feed quota, and EVs were derived by estimating profit at farm level before and after improving a single trait by one genetic standard deviation, while keeping the other traits constant. Estimated EVs (€/kg production/trait unit) were: -0.02 for thermal growth coefficient (TGC), 8.60 for fillet yield, 14.28 for feed conversion ratio (FCR), 0.77 for RTFS survival and 3.79 for overall survival. EVs for both survival traits showed non-linear patterns across phenotypic means. Joint analysis demonstrated that each trait’s EV was influenced by the phenotypic level of the other survival trait, with overall survival consistently showing the higher EV. In conclu-sion, this study provides the first EV estimates for organic rainbow trout production and shows that EVs for survival traits exhibit non linear sensitivity to their own phenotypic levels and those of other survival traits. These findings highlight the need for periodic re estimation of EVs as trait means change and offer guidance for designing economically optimised breeding goals in organic aquacul-ture.

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