Résumé
Anthropogenic activities have led to the persistent build-up of trace metals and organic pollutants in coastal ecosystems, threatening aquatic life. Gilthead seabream, a commercially valuable species, often inhabits Mediterranean lagoons that function as vital nursery grounds. In this study, we examined 93 juvenile seabreams from three Tunisian lagoons to evaluate contamination levels and their effects on otolith morphology. We measured inorganic and organic contaminants in fish muscle and investigated their potential effects on otolith shape and asymmetry. Clear contamination signatures emerged across sites: Tunis Lagoon exhibited the highest levels of contamination, followed by Ghar El Melh, while El Biban Lagoon appeared relatively pristine. Relatively elevated levels of metals (e.g., Pb, Ni, Be) and persistent organic pollutants (e.g., PCBs, DDTs, PBDEs) were observed in the more impacted lagoons.Notably, we found that otolith shape and fluctuating asymmetry were significantly associated with contaminant exposure, even after accounting for natural variables like fish size and lipid content. Specific pollutants, especially Cu, Be and PCBs, were linked to altered otolith shape and increased asymmetry, suggesting disrupted biomineralisation. Greater asymmetry observed in the left otolith suggests that sub-lethal stress impairs developmental stability.Although contaminant levels generally fell below food safety thresholds, the observed effects on otolith development raise concerns about functional consequences and underlying physiological stress. Our results highlight otolith asymmetry as a sensitive bioindicator of environmental stress in wild fish. By integrating shape analysis with contaminant profiling, this study offers a powerful tool for assessing pollution impacts in vulnerable Mediterranean nursery habitats.