90-Year Study Reveals Rich Shark and Ray Populations in Greek Waters

In a groundbreaking study spanning nine decades, environmental organisation iSea has revealed a comprehensive overview of sharks and rays inhabiting Greek seas.

The extensive survey uncovered 4,540 records across 33 shark species, 29 species of rays and skates, and one chimaera, showcasing the rich biodiversity of these waters.

This ambitious research, the result of 90 years of data collection from various sources, underscores the importance of Greek waters as a habitat for chondrichthyans, a group of cartilaginous fish that includes sharks, rays, and chimaeras. The findings will be presented at the prestigious Pan-European Shark and Rays Association (EUSA) 2024 Conference in Thessaloniki from October 21-24. The conference, hosted by the Region of Central Macedonia and the Municipality of Thessaloniki, is one of the largest gatherings of experts dedicated to the study and conservation of these species.

Roxanne Naasan Aga-Spyridopoulou, iSea’s program manager, spearheaded the research, analyzing data from various sources including academic theses, biodiversity databases, social media, citizen science initiatives, and official government reports. Her findings, which emphasise the presence and distribution of chondrichthyans in Greek seas, are intended to provide a foundation for future research efforts.

Speaking to the Athens/Macedonian News Agency, Ms. Spyridopoulou noted that the study provides critical insight into the distribution of these species, which can now be used to direct future research projects. "The map we've developed, based on records spanning 90 years, shows that sharks and rays are present in virtually every marine area we examined," she said. One key revelation is that more than half of the records (55%) were unpublished in scientific journals, while 20% were contributed through citizen science, highlighting the significant role that non-professional data collection plays in understanding marine biodiversity.

Ms. Spyridopoulou also pointed out that recent years have brought a surge in data. "From 2010 to 2023 alone, we recorded more than 2,500 new entries, reflecting how our knowledge of these top predators has grown significantly in recent times," she said.

The study also addresses the long-standing knowledge gap surrounding sharks and rays in the Mediterranean. Despite evidence of their presence dating back to Aristotle, it is only in the last two decades that systematic research has been conducted. Even so, information about their spatial distribution remains limited, with most studies focusing on biological or fishery-related parameters.

The upcoming EUSA 2024 conference, themed "Stronger Collaboration for More Effective Conservation," aims to enhance interdisciplinary cooperation, expand opportunities for young researchers, and boost representation from regions like the Balkans and the Middle East. These areas, where data on sharks and rays are often scarce, stand to benefit significantly from this shared knowledge.

iSea's study, along with the visual map created by Ms. Spyridopoulou, will undoubtedly serve as a catalyst for future conservation efforts, shedding light on the vital role Greek seas play in supporting these remarkable marine species.

(Source: To Vima)