PERRIN ET AL.: GROWTH AND REPRODUCTION OF SPOTTED PORPOISE 



take place (age about 7 to 12 layers) and that 

 about 2 to 4 layers are required to attain "adult" 



- 20 



UJ 

 CO 



It: 15 



y 



< 



UJ 

 U- 



o 



z 

 o 

 I- 

 a: 

 o 



CL 



o 

 <r 

 a. 



10 



n 



rui 



I I I I I I ' ' ' I 



JFMAMJJASONDJFMAMJJASONDJFMAMJJiSOND 



1971 1972 1973 



(n = 34) (n = l52) (n = l87) 



MONTH OF BIRTH 



FIGURE 17. —Predicted month of birth for 373 fetuses oiStenella 

 attenuata, based on fetal growth curve. 



testes size (500 to 2,000 g). The third largest 

 testes were possessed by an animal (202 cm long, 

 80 kg, discussed above) that had nonreadable 

 teeth that were worn to the gum in all four tooth 

 rows. Such tooth wear may be a correlate of rela- 

 tively great age. 



The diameter of the seminiferous tubules be- 

 gins to increase rapidly at body length of about 

 155 to 170 cm (Figure 20), or at lengths about 15 

 cm shorter than those at which testes weight be- 

 gins to increase. Tubule diameter is definitely 

 correlated with body length until at least about 

 200 cm. The heaviest male (91 kg) had the largest 

 tubules. The plot of tubule diameter on layers (Fig- 

 ure 21) indicates that the tubules enter a rapid 

 development stage at 6 to 11 layers, before the 

 onset of a rapid increase in testes weight (Figure 

 19). Asymptotic diameter is about 170/xm and ap- 

 pears to be attained by 10 to 14 layers. 



2400 



2000 



— 1,500 



X 

 O 



UJ 



LlI 



I- 



C/) 

 UJ 



1,000 



500 



v.. «• 



M • • . • . 



t • I.. 



I« 





80 



90 



100 



10 



■f- 



»«»* 



m* * t , 1.. 



• ••! ' 1 , ** 



. -••• • . • 



120 



130 



180 



190 



200 



140 150 160 170 



BODY LENGTH (cm) 

 Figure 18. — Scatterplot of testes weight on body length in Stenella attenuata 



210 



220 



230 



247 



