Size at Maturity, Reproductive Cycle, Fecundity, and Depth Segregation of the Deep Sea Squaloid Sharks Centroscymnus owstoni and C. coelolepis in Suruga Bay, Japan

Abstract

Specimens of the deep sea sharks, Centroscymnus owstoni and C. coelolepis, were collected from Suruga Bay, Japan to examine their reproductive habits. Size at maturity for both species was about 700 mm TL in males and 1000 mm TL in females. Neither species has a well defined breeding season. The reproductive cycle appears to extend over one calendar year. The ratio of males to females was approximately 1: 1 for C. owstoni and 1: 2 for C. coelolepis. Litter size ranged from 16 to 28 for C. owstoni and from 15 to 29 for C. coelolepis. Total number of mature ova, fertilized ova and embryos tended to increase with size of the female. Females of both species displayed a well defined pattern of depth segregation by stage of maturity. The catch depths of pregnant females for both species were shallower than those of non-pregnant ones. However, pregnant females with full-term embryos were not caught in shallow waters of Suruga Bay. © 1988, The Japanese Society of Fisheries Science. All rights reserved.