Revealing the presence and genetic identification of the rare and critically endangered deep-sea Sandy skate (Leucoraja circularis) in the Adriatic Sea

The sandy skate (Leucoraja circularis) is one of the rarest deep-sea batoids in the Mediterranean Sea and has long been considered absent or exceptionally rare in the Adriatic Sea. Here, we report seven confirmed records obtained through fishery-dependent monitoring along the upper continental slope of the southern Adriatic Sea off Vlor¨e, Albania. All individuals were captured at depths between 400 and 600 m, with six of seven records concentrated within a narrow depth interval (410–423 m) off the Karaburun Peninsula and Sazan Island. Both juvenile and adult specimens were documented, indicating the presence of multiple ontogenetic stages within the study area. These findings represent the first verified records from Albanian waters and constitute the largest dataset available for the species in the Adriatic Sea to date. All individuals were found dead upon retrieval, indicating alarmingly high at-vessel mortality for this critically endangered species. Molecular data confirmed species identification and provided new COI and NADH2 mtDNA sequences, representing the first regional molecular dataset for L. circularis, crucial for the establishing of a baseline for future assessments. Moreover, genetic analyses highlighted the occurrence of new private haplotypes in Albanian waters in both COI and NADH2 datasets, suggesting the presence of a possible resident population in the studied area. Together, these results confirm the occurrence of L. circularis in the southern Adriatic Sea and identify this region as a previously overlooked component of the species’ Mediterranean range, with important implications for monitoring, management, and conservation of one of the Mediterranean’s most threatened deep-sea skates.