Assessment of the Growth Patterns of Luciobarbus graecus (Teleostei) in the Upper, Middle, and Lower Basins of the Three Rivers in Türkiye

<strong>Objective:</strong> Following recent taxonomic revisions, Luciobarbus graecus (Steindachner, 1895), previously considered endemic to Greece, is now recognized as a species with a broader distribution across western Greece and western Anatolia (Türkiye). This study investigated the condition factors and length-weight relationships of L. graecus in Western Anatolia across various river basins and habitat types. <strong>Materials and Methods:</strong> Using seine nets, cast nets, and electroshock devices, 241 individuals were sampled from the upper middle and lower reaches of the Büyük Menderes and Gediz rivers as well as the Kocabaş Stream. <strong>Results:</strong> The findings showed that L. graecus usually exhibits isometric growth at most sampling locations, with negative allometric growth noted in the Kocabaş Stream and the upper Büyük Menderes River basin. There was a modest variation in the condition factor values between the regions, indicating that the populations were stable and generally healthy. The maximum length values found in this study are greater than those previously documented for the species. Additionally, the study offers the first information on the length-weight relationship from these particular river systems. <strong>Conclusion: </strong>These results greatly aid in the conservation and management of L. graecus, which is becoming increasingly endangered due to habitat modification, pollution, hydrological changes, and invasive species. They also offer a useful baseline for upcoming ecological assessments. This study contributes to our knowledge of the indigenous ichthyofauna of Türkiye and emphasizes the significance of basin-specific population monitoring by providing insights into the species ecological performance across various freshwater settings.