As part of meagre ( Argyrosomus regius) restocking programme in the Balearic Islands (W. Mediterranean) specimens were reared in captivity and experiments to determine the best batch marking procedure prior to release were carried out. Immature fish otolith marking with oxytetracycline failed to mark the otoliths at 37 (per mil) salinity, while alizarine red bath at a concentration of 60 mg L −1 for 22 h proved to be successful in >90% of the otoliths, with low mortality rates (<8%). The mark was present irrespective of fish age or of time elapsed since marking. The daily nature of the otolith growth increment was validated for fishes 53–305 days of age. Otolith and fish growth showed variability depending on year class and water temperature, with growth rates lower than those experienced in the wild.