Abstract: We analyzed the stomach contents of a Cuvier's beaked whale (Ziphius cavirostris) stranded on Suruga Bay, Pacific coast in the central Japan in September 1999. A total of 485 squid lower beaks were found in the stomach. Some pieces of crabs were also found, but no fish remains. Squids included six identified species; Gonatus spp. and Taonius pavo were the most important components. The prey species composition was similar to those in the limited published information from the colder waters in the northern North Pacific and northern North Atlantic, although the Kuroshio warm current meets the present stranding site. Most of the estimated dorsal mantle length of G. onyx and T. pavo ranged in 140-360 mm, which corresponds to the adult or sub-adult size of these species. The prey species and their size suggest that Cuvier's beaked whale dive to deeper than 300 m layer. Crabs in the stomach contents suggest foraging even to the bottom. Present and previous studies suggested that Cuvier's beaked whales off Japanese waters dive to 300-1000 m to forage.
Key Words: CUVIER'S BEAKED WHALE; FORAGING DEPTH; GONATUS ONYX; PACIFIC COAST OF CENTRAL JAPAN; STOMACH CONTENTS; TAONIUS PAVO; ZIPHIUS CAVIROSTRIS
Document Type: Research article