Distribution of Chondrichthyans in the Greek Seas

The Greek seas have hosted a diversity of sharks and rays since antiquity, with Aristotle providing the earliest detailed descriptions in his History of Animals, while the first modern documented record dates back to 1858. Despite this long history of attention and the acceleration of research on elasmobranchs over the past two decades, information on their spatial distribution remains fragmented, with most studies focusing on biological and fisheries-related parameters at low taxonomic and/or spatial resolution. This is concerning given that over 50% of Mediterranean chondrichthyans are now threatened with extinction. The present study reconstructs the distribution of extant species in the Greek seas by integrating published literature, mass and social media, biodiversity platforms, citizen science programs, research projects, and national datasets. Although records were compiled from 1858 onwards, only those starting from 1942 contained sufficiently precise locality information to be georeferenced. The review yielded 5596 spatial presence records of initially 67 species; however, after data validation, 62 species were confirmed: 33 shark species, 28 batoid species, and 1 chimaera species, of which 54.8% were from research programs, 30.5% were from published research, and 14.4% were from citizen science and were previously unpublished. These records enrich knowledge of threatened and data-deficient taxa and may serve as a useful baseline for future analyses and distribution modeling, as well as for informing marine spatial planning and conservation prioritization efforts in the eastern Mediterranean.