Individually specific seasonal cycles of embryonic development in cultured broodstock females of the black rockfish, Sebastes schlegeli

Abstract

Viviparous black rockfish, Sebastes schlegeli, mate in November, fertilization occurs in the following April and birth of larvae in May at the Miyako Station of the Japan Sea-Farming Association (JASFA). Developmental stages of intra-ovarian embryos in individual female black rockfish reared in an indoor tank were examined using a cannulation method on almost the same day (April 24 or 25) for three successive years. The estimated delivery occurred near the predicted date regardless of the year. This indicates that black rockfish have individually specific annual cycle of fertilization and embryonic development. Understanding individual annual cycles of parturition is very useful for efficient broodstock management and juvenile production for aquaculture and stock enhancement.