Abstract
Goose‐beaked whale ( Ziphius cavirostris ), a cosmopolitan odontocete, is commonly found in the Mediterranean Sea. This study, the first to examine the stomach contents of the goose‐beaked whale in the Aegean Sea and Levantine Basin, reveals key aspects of its diet. The stomach contents of one whale from Seferihisar, Türkiye, in 2016, and five from a mass stranding on Cyprus in February 2023 were analyzed. A total of 1,448 lower beaks from 16 cephalopod species were identified, with six species— Octopoteuthis sicula , Ancistrocheirus lesueurii , Histioteuthis reversa , Chtenopteryx sicula , Chiroteuthis veranii , and Todarodes sagittatus —comprising the primary diet. Four species— Loligo forbesii , Pyroteuthis margaritifera , Pterygioteuthis giardi , and Brachioteuthis riisei —were recorded for the first time in goose‐beaked whale stomachs. Their prey preference is generally pelagic cephalopods, though benthic or demersal species are occasionally eaten. The high species diversity and the presence of species not found in other studies may be due to differences in cephalopod fauna characterized by seabed and other oceanographic features of the eastern Mediterranean. The Mediterranean population is genetically divided into western and eastern subpopulations, and their diets appear to differ.