730 



Fishery Bulletin 100(4) 



160 

 140 

 120 



e 100 



60 

 40 

 20 - 



N =253 



o Adult 

 A Juvenile 



o ^ 

 o c£) c 



OO Oo 



OO o 



o ®o 



n° 



0,0*0 



o o 



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80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 

 Fork length (cm) 



Figure 2 



Relationship of right testis length to fork length. 



reproductive organs were measured for 267. Development 

 of the siphon sacs, as well as internal male reproductive 

 organs — testes (diameter and length), epididymis, and 

 ampulla epididymis — is gradual in relation to FL (Fig. 2). 

 The development of the claspers. however, shows a dis- 

 tinct inflection (Fig. 3). Claspers begin to elongate when 

 the males approach 120 cm FL, and rapid clasper growth 

 begins at 135 cm FL and slows by about 170 cm FL when 

 they have reached their maximum adult size of 19-24 cm. 



The largest shark with uncalcified claspers but containing 

 spermatophores in the ampulla epididymis was 176 cm FL, 

 and the smallest shark with calcified claspers, but with 

 no spermatophores, was 166 cm FL. Claspers rotate freely 

 at all sizes in the porbeagle; therefore clasper rotation is 

 not a good measure of maturity. Males of 135 to 184.5 cm 

 FL are in a transitional phase leading to maturity. At this 

 stage, claspers are lengthening and the head of the clasper 

 (rhipidion) is beginning to develop, whereas at 149 cm FL 



