732 



Fishery Bulletin 100(4) 



90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 



Fork length (cm) 



Figure 5 



Relationship between ovary length (mm) and fork length (cm) in the porbeagle shark. 

 Juveniles and adults are indicated. 



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90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 



Fork length) (cm) 



Figure 6 



Relationship between oviducal gland diameter (mm I and fork length (cm) in the por- 

 beagle shark. Juveniles and adults are indicated. 



testes. Spermatophores in the ampulla epididymides were 

 at their greatest volume in September-December; in Feb- 

 ruary-May relatively few spermatophores were observed, 

 and by June the concentration started to increase. 



Female length at maturity 



Reproductive data were obtained from 382 female porbea- 

 gle sharks ranging in size from 94 to 288 cm FL, of which 

 reproductive organs were measured for 284. The relation- 

 ship between the measurements of internal reproductive 

 organs (ovary length and width, anterior uterus length 



and width, and shell gland (oviducal gland) width to FL) 

 showed a sharp increase between 210 and 220 cm FL 

 (Figs. 5 and 6). Oocytes are not visible to the naked eye in 

 juveniles less than about 200 cm FL, and in larger, imma- 

 ture females, small, clear, yolkless oocytes range in size 

 from 0.5 to 3.7 mm in diameter. In mature females, vitel- 

 logenic oocytes range from 2.2 to 7.0 mm. The increase in 

 oocyte diameter, as well as the development from clear 

 yolkless oocytes to vitellogenic oocytes, occurs between 

 210 and 225 cm FL (Fig. 7). Criteria for maturity in female 

 porbeagles include the presence of embryos or fertilized 

 ova in the uteri, and indications of past pregnancy, such 



