Chondrichthyan species as by-catch: A review on species inhabiting Turkish waters
Elizabeth Grace Tunka Bengil, Nuri Başusta
Marine School, Girne American University, University Drive, Karmi Campus, Karaoglanoglu, Girne, TRNC, TURKEY
Akdeniz Koruma Derneği, Doga Kent Villaları, 3360 sokak, No.7/16, Urla, Izmir, TURKEY
Fisheries Faculty, Firat University, 23119, Elazig, TURKEY
Chondrichthyan or cartilaginous species, throughout the world, are found among fisheries by-catch. In this study, 52 studies conducted between 1991 and 2018 in Turkish waters were reviewed to assess the status of chondrichthyan species as by-catch. Geographic coverage was grouped as; Black Sea (the number of studies 5), Sea of Marmara (6), Aegean Sea (25), and Levantine Sea (16). Results showed that there were differences in by-catch amounts when sharks, rays and chimaeras were compared according to geographical grouping. When by-catch ratios of listed species were analyzed it showed that almost half of the by-catch was comprised of small spotted catshark, Scyliorhinus canicula (Linnaeus, 1758), followed by blackmouth catshark, Galeus melastomus Rafinesque, 1810. In case of rays, the most common species of by-catch was thornback ray, Raja clavata Linnaeus, 1758, followed by common stingray, Dasyatis pastinaca (Linnaeus, 1758). Among all reported species concerned, 9 were Critically Endangered, 8 Endangered, 7 Vulnerable, 13 Near Threatened, 8 Least concern, 9 were Data Deficient, according to IUCN Red List, corresponding to half of the Turkish cartilaginous fauna. This review aims to provide on the by-catch of cartilaginous species caused by scientific or commercial fisheries activities in the Turkish waters emphasizing on long-needed conservation action plans for future sustainability of these cartilaginous species.
Keywords: Chondrichthyan species, by-catch, Turkish waters, threatened species