Turkish Journal of Fisheries and Aquatic Sciences
2019, Vol 19, Num, 6 (Pages: 475-484)
Feeding Ecology of Four Demersal Shark Species (Etmopterus spinax, Galeus melastomus, Scyliorhinus canicula and Squalus blainville) from the Eastern Aegean Sea
2 Faculty of Fisheries, Ege University, P. O. Box 35100 Izmir, TURKEY
3 Mediterranean Conservation Society, Doğa Vilları P.O. Box 35430 Izmir, TURKEY
4 Çukurova University, Fisheries Faculty, P.O. Box 01330, Balcali/Adana TURKEY DOI : 10.4194/1303-2712-v19_6_03 Viewed : 3670 - Downloaded : 2905 In this study, the diet composition and trophic ecology of four demersal chondrichthyan species; Etmopterus spinax, Galeus melastomus, Scyliorhinus canicula and Squalus blainville were studied in the eastern Aegean Sea. In the stomachs of the samples which mostly consisted of juvenile individuals, a total of 97 prey taxa were identified. Teleost fishes were the most important prey group. The diversity of stomach content ranged between 15 species in E. spinax. and 70 species in S. canicula. The dietary breadth of G. melastomus and S. canicula were found to be narrower than the other two species examined. In addition, high niche overlap scores were detected amongst the species. All of the examined species had trophic levels higher than 4; with the highest trophic level being 4.20 and belonging to E. spinax. Comparisons among calculated trophic levels by global methods and a regional weighted method, which is proposed in this study, showed that the regional method offers remarkable advantages that can be used to reduce the uncertainty of the estimations. Keywords : Elasmobranches, Diet composition, Niche overlap, Trophic level, The Eastern Mediterranean