This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.
Reproductive biology of the blue shark, Prionace glauca, in the western North Pacific Ocean
The reproductive biology of the blue shark, Prionace glauca, in the western North Pacific Ocean was investigated to contribute to future stock assessments because of limitations of recent studies and the lack of information about the reproductive cycle. Reproductive data were obtained from 490 males (precaudal length [PCL], 33.4â252.0 cm) and 432 females (PCL, 33.4â243.3 cm). Size at 50% maturity was estimated to be 160.9 cm for males and 156.6 cm PCL for females. Litter size varied from 15 to 112 (mean, 35.5) and was positively correlated with maternal PCL. Parturition, ovulation, and mating occurred sequentially from spring to summer. The gestation period was estimated to be 11 months. The ovarian follicles of pregnant females developed synchronously throughout the gestation period along with embryonic growth, indicating that females reproduce annually. Our results show that the productivity of North Pacific blue sharks is higher than previously thought based on larger fecundity and a shorter reproductive cycle. These new findings will improve future stock assessments and provide management advice.
MF16101 Accepted 29 January 2017
© CSIRO 2017