Tracing the origin of "Durdubak": DNA barcoding reveals that the widely used fish bait is a recently described leech species from Türkiye

In this study, a DNA barcoding method was successfully applied to identify the taxonomic affiliation and the geographical origin of the so-called “Durdubak” leeches, which are commonly used as fish bait in Serbia and the Balkans and are imported to Western and Central Europe for this purpose. Our results indicate that the "Durdubak" specimens imported from Serbia to Germany in 2006, and previously identified morphologically as Trocheta danastrica Stschegolew, 1938, molecularly belong to T. kesirvenensis Sağlam, Saunders & Shain, 2025, a species previously known only from the Aegean region of Türkiye. This study demonstrates that traceability of leeches used as fish bait may become increasingly important in the future, as fraudulent labeling or misidentification not only undermines consumer confidence in the bait market but also poses a threat to populations of native leech species.