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Abstract [eng]

The impacts of non-native species might be noticeable years after their initial introduction. Determining the age of a recently established non-native fish population can be important to identify the year of its introduction. Although well-established, the accuracy and reproducibility of age determination techniques are not often discussed. In this manuscript, we propose a standardised method for the determination of age in scale-less fishes. We use the channel catfish Ictalurus punctatus as a model species and we highlight the importance of the pectoral spine section location to produce accurate age determinations. Our results show that decalcification is not neces-sarily needed and that cuts to the basal section of the spine shaft produce the clearest and most reliable results.