A preliminary study on marine top predators inhabiting Gökçeada Island, the North Aegean Sea

A preliminary study on marine top predators inhabiting Gökçeada Island, the North Aegean Sea

Nur Bikem Kesici, Cem Dalyan, Onur Gönülal, Aylin Akkaya, Patrick Lyne, Suna Tüzün, Belen Yıldırım

ORCID IDs: N.B.K. 0000-0002-9636-1649; C.D. 0000-0002-7386-5641; O.G.0000-0002-5559-3953; A.A. 0000-0002-0414-770X;
P.L. 0000-0002-8326-5180; S.T. 0000-0003-2876-788X; B.Y 0000-0002-4768-0213

Division of Hydrobiology, Department of Biology, Faculty of Science, Istanbul University, Istanbul, TURKEY
Faculty of Aquatic Sciences, Istanbul University, Ordu Street, No:8, Laleli, Fatih, Istanbul, TURKEY
DMAD-Marine Mammals Research Association, Antalya, TURKEY
Sea Mammal Research Unit, University of St. Andrews, Scotland, UNITED KINGDOM


Marine top predators, such as sharks, teleosts and cetaceans, are great indicators of a healthy ecosystem. The primary goal of this paper is to fill the knowledge gaps on top predators in Gökçeada Island located in the North Aegean Sea. Data on marine top predators were collected through Local Ecological Knowledge. Besides, visual and acoustic field surveys were carried out in the summer and autumn of 2019 and winter of 2020. According to the results of the current study, a total of 464 individuals were reported via social media platforms and questionnaires applied to stakeholders as fishermen, divers and harpooners. Delphinus delphis Linnaeus, 1758, Tursiops truncatus (Montagu, 1821) and Physeter macrocephalus Linnaeus, 1758 were detected during approximately 15 hours of acoustic recording. The records of Carcharodon carcharias (Linnaeus, 1758), Isurus oxyrinchus Rafinesque, 1810, Xiphias gladius Linnaeus, 1758, Thunnus thynnus (Linnaeus, 1758), D. delphis, Stenella coeruleoalba (Meyen, 1833), T. truncatus, Grampus griseus (Cuvier, 1812), P. macrocephalus, Ziphius cavirostris (Cuvier, 1823), Monachus monachus (Hermann, 1779) were listed in this study. A total of 358 individuals of X. gladius and T. thynnus were reported between the years 2017-2020, being the most abundant top predators in the area.

Keywords: Marine apex predators, sharks, large teleosts, marine mammals, local ecological knowledge

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