The Nordic countries Denmark, Sweden and Finland, has in this project worked towards solving the long lasting problem of creating an objective and reproducible method of ageing Eastern Baltic Cod. A database has been co-ordinate, containing over 45 000 entries with otolith weights including traditional ageing, with the purpose to find a method how to infer age of fish from otolith weight. A review of the state of the art using otolith weight as a proxy for age has been made with the aim to develop and implement a method addressing the specific case of the Eastern Baltic Cod. A possible method has been identified and the process of developing of a necessary calibration sample has been investigated. Based on the results of this project new funds has been granted from EU involving all relevant countries in the Baltic with the aim to further develop and refine the suggested method.