Oncorhynchus mykiss is one of the dominant salmonids farmed in Europe and North America, second only to Salmo salar. In addition, it is one of the most widely studied model fish species in the wild and in captivity. Yet, the living conditions and the husbandry systems that maximise the welfare of this species are still to be defined, developed, and improved. This lack is quite incomprehensible, given the background and the availability of research performed on this species. The low FishEthoScore is mainly due to the need of space and substrate and to high levels of aggression, stress, and high deformations under farming conditions. Grow-out typically takes place in ponds or raceways, sometimes also in cages. There are two strains in O. mykiss: the anadromous one, also called Steelhead trout, and the potamodromous Rainbow trout. Aquaculture populations probably combine genes of both strains. In anadromous FISHES, throughout the life history, morphology, behaviour, and environmental requirements change. Husbandry systems and practices need to take such differences into account in order to achieve and maintain high welfare. The development of new rearing strategies to optimise the husbandry practices as well as handling with special care would be a step forward to solve some specific welfare concerns. Finally, providing feed which contains a lower amount of fish components from wild catch has proven feasible for this species in lab studies, so a protocol for application in farming conditions has to be developed.
For details see: WelfareCheck | farm (latest major release: 2022-12-27)Series 16 of FishEthoGroup's podcast programme on the fair-fish database entails episodes on Morone saxatilis (Striped bass), Barbonymus gonionotus (Silver barb), and Oncorhynchus mykiss (Rainbow trout). In snippets of about 3 min each, you get to know the most important things we researched on these species for the fair-fish database. To listen to the episodes, click on the links above or go to FishEthoGroup.
In 2022, our colleagues from FishEthoGroup were invited to write a report for the Aquaculture Advisory Council of the European Commission on the topic of "Using ethology to improve farmed fish welfare and production". This report was recently published anew with an updated appendix. For this report, FishEthoGroup collaborated with the fair-fish database to give a summary of the situation of 5 of the most frequently farmed species in Europe (Sparus aurata, Dicentrarchus labrax, Oncorhynchus mykiss, Salmo salar, Cyprinus carpio). We from the fair-fish database used the opportunity to update these 5 profiles (of which you have read in this News section in the past months). Among them was that of Salmo salar, the Atlantic salmon, which was enriched with a plethora of papers and was transferred to our latest more transparent and user-friendly formatting scheme. Thanks to the update, we could get rid of a couple of question marks in the welfare assessment, but the new findings only manifested what was hinted at before: except at slaughter, Salmo salar cannot experience good welfare in captivity even under the best possible conditions.
The Short profile of Oncorhynchus mykiss, Rainbow trout, was one of the first ones published in the FishEthoBase - it was time for an update! Please find the Short profile with more detailed information, selected papers since 2017 as well as our new consistent age class and label structure here. Unfortunately, the FishEthoScore did not improve in the last 6 years since we first assessed O. mykiss' welfare potential in captivity and remains very low.
