Peres and Vooren: Sexual maturation, reproductive cycle, and fecundity of Galeorhinus galeus 



659 



and varied from 400 to 1600g, including the 

 epigonal organ of 25-60 g. Maturing ovaries con- 

 tained 12 to 34 follicles of uniform size, with 

 diameter greater than 3.5cm. Such ovaries oc- 

 curred in females larger than 122 cm TL (Fig. 5). 



The smallest pregnant female was 118cm TL. 

 Incidence of pregnancy increased to about 50% 

 at body sizes greater than 130 cm (Table 2). The 

 developing uterus appeared as a strip of white 

 tissue with diameters up to 0.3cm in females of 

 less than 110cm. The uterus widened first at its 

 posterior end, becoming bottle-shaped at lengths 

 of 110- 125 cm TL, with a diameter of 1.0-2.3 cm 

 at its widest part. Fully-formed uteri, uniform in 

 width, measured 2.0-4.0 cm in diameter and oc- 

 curred in females larger than 121cm TL. All non- 

 gravid females with total lengths greater than 

 128cm possessed such uteri. 



The width of the nidamentary gland varied 

 about 0.4 cm in females of less than 112 cm, and 

 increased to values between 1.8 and 4.6cm in 

 females larger than 125 cm TL (Fig. 6). 



Based on color and size of the ovarian follicle, 

 width of the nidamentary gland and uterus, and 

 the incidence of pregnancy, it is concluded that 

 sexual maturity first occurred at 118 cm TL, 50% 

 maturity at 123cm TL, and full maturity at 128 

 cm TL. In the nongravid adult female, the uterus 

 had a diameter of 2.0-4.0 cm, the nidamentary 

 gland was 1.8-3. 5 cm in width, and the ovary con- 

 tained yellow follicles of diameters 1.4-5. 5 cm. 



In one nongravid female of 154.5cm TL, the 

 ovary was reduced to four atretic follicles with 

 diameters less than 0.4 cm, and the nidamentary 

 glands were reduced in width (Fig. 6). The dor- 

 sal coloration of the body of this female was light 

 grey with dark blotches. This 41-year-old female 

 (Ferreira and Vooren 1991) was considered senile, 

 the only such specimen encountered. 



Reproductive cycle of the female 



If the reproductive cycle of the female is syn- 

 chronous at the population level, fertilization and 

 birth should occur at definite seasons, and at any 

 given time all gravid females should contain em- 

 bryos in the same stage of development. If, in 

 addition, the reproductive cycle lasts three years, 

 three distinct categories of adult females are 

 expected to simultaneously exist. A time-series 

 of measurements of embryos and ovarian follicles, 

 histological smears of the nidamentary gland, and 

 seasonal records of ovulation showed that this 

 was the case. 



