Individual age data for short-beaked common dolphins (Delphinus delphis ponticus) stranded on the coasts of Ukraine and Romania, 2001–2023

This dataset contains individual age estimates and associated biological data for 22 short-beaked common dolphins (Delphinus delphis ponticus) stranded on the Black Sea coasts of Ukraine and Romania between 2001 and 2023. The Black Sea short-beaked common dolphin is an endemic subspecies, currently classified as Vulnerable by the IUCN, that experienced severe population decline during the twentieth century. Up-to-date life-history data for the subspecies — including age structure and maximum lifespan — remain scarce; the present dataset provides individual-level age estimates intended to support demographic and conservation assessments. For each specimen the dataset provides: a sequential identifier; the date of stranding; the area of the Black Sea where the carcass was recovered; standard body length where measured; sex where determined; and two independent blind age estimates obtained by counting growth layer groups (GLGs) in dentine, together with the reconciled final age. Ages range from 4 to 32 years; the oldest individual, a 32-year-old female, represents the highest age recorded to date for a free-ranging short-beaked common dolphin globally. Teeth were extracted from the lower jaw, decalcified using RDO (Rapid Decalcifier Original), sectioned at 20 µm on a freezing microtome, and stained with toluidine blue. GLG counts were performed independently by two readers blind to each other's results, with one GLG corresponding to one year of life. Full methodology and discussion are provided in the accompanying manuscript (Vishnyakova, Paiu & Gol'din, Marine Mammal Science). When reusing these data, please cite both this dataset (via its Zenodo DOI) and the accompanying manuscript.