Some Biological Aspects of the Deep Sea Squaloid Shark Centroscymnus from Suruga Bay, Japan

Abstract

Specimens of the deep sea sharks, Centroscymnus coelolepis and C. owstoni, were caught with bottom drop line, bottom longline, and bottom gillnet in Suruga Bay, Japan. The catch rates of males were higher than catch rates of females on the bottom drop lines. In both species, the females were distributed in deeper layers than the males, but the distribution of C. owstoni seemed to extend to shallower layers than that of C. coelolepis. The smaller individuals of both species, those below 600 mm in total length (T.L.), were thought to inhabit separate areas such as the waters outside of the bay. The stomach contents of both species consisted mainly of fish and squid. Empty stomachs were more frequently found during the daytime than at night. The proportion of the weight of the intestinal contents to the weight of the intestine was found to be higher during the night than during the day. © 1984, The Japanese Society of Fisheries Science. All rights reserved.