FISHERY BULLETIN: VOL. 85. NO. 2 



Table 4.— Estimated age and size at 1st, 50% and 100% maturity for 



given in cm 



'Denotes samples from 1980-82 study only. 



peak month of larval extrusion. The external ap- 

 pearance of individual ovaries indicates that larvae 

 are in the eyed stage and ready for release through- 

 out the ovary. 



The total number of mature females observed dur- 

 ing the reproductive months, and the percentage 

 containing eyed larvae is presented for three com- 

 mercially important species (Figs. 8-10). For the 

 years 1981-85, variations in the months of parturi- 

 tion and/or the peak month is seen. SebaMes ento- 

 melas (Fig. 8) showed an annual variation in the 

 months of parturition but not in the peak months 

 (January-February). The peak month for S. goodei 

 (Fig. 9) varied from December to February, and in 

 iS. paucispinis (Fig. 10) from December to March. 

 A variation in which months larval extrusion occurs 

 is seen in all three species. Chi-square tests showed 

 the percentages to be dependent upon year and 

 month. Therefore, there is a relationship between 

 the percent-number of mature females with eyed lar- 

 vae seen in a particular month, and reproductive 

 year. 



DISCUSSION 



The reproductive biology of Sebastes follows the 

 sequence of spermatogenesis, vitellogenesis, mating, 

 ovulation, fertilization, and larval extrusion (Moser 

 1967b). As in other \dviparous fishes (Turner 1947), 

 sperm can apparently survive within the ovary for 

 many months. In S. mentella, ovulation and the 

 activation of sperm coincide with a change in pH 



(Sorokin 1967). The histological evaluation of the 

 gonads in Sebastes of northern California confirms 

 that spermatogenesis is generally completed and 

 mating occurs before the completion of vitello- 

 genesis. The length of time males are fully ripe can 

 be up to 2 months in various species, and the delay 

 between the time males are fully ripe and fertiliza- 

 tion (sometimes up to 4 months) indicates that 

 mating does not coincide with fully mature ova 

 (Figs. 1-7). Testes are observed in decreasing 

 degrees of ripeness after spermatogenesis has 

 ceased. This indicates that one mating does not void 

 the testes; males may mate more than once per 

 season. Ovulation in teleosts is regulated by steroids 

 and prostaglandins, which in turn are influenced to 

 some degree by temperature, pheromones, or 

 spatial/temporal cues (Stacey 1984). The presence 

 of sperm in the ovaries of Sebastes does not trigger 

 final oocyte maturation and ovulation; therefore, 

 ovulation is probably influenced by environmental 

 conditions. Thus knowing which conditions influence 

 ovulation is necessary to determine some of the fac- 

 tors contributing to a successful reproductive year, 

 as measured by the percent mature females vdth 

 eyed larvae. 



The costs of reproduction for females include the 

 development of a highly vascular network through- 

 out the ovaries, the nourishing of developing em- 

 bryos (Boehlert and Yoklavich 1984), and the metab- 

 olism of waste products from the embryos (Moser 

 1967a). The ovaries must accommodate the added 

 gonadal weight and volume until larval extrusion. 



242 



