Growth is generally the first process analysed in studies of fish stock and results in the most immediate application of age data, as the majority of analytical stock assessments use age-based models (Panfili *et al.* 2002). Age data derived from reading solid structures is generally limited due to the cost and complexity involved. In contrast, the collection of length information is relatively simpler and less costly, thus catch-at-length data are more frequently available. Considering age and length are correlated, it is possible to determine catch-at-age from catch-at-length data.