586 



Fishery Bulletin 102(4) 



£ 

 o 

 O 



V a 



nnj 



60 70 80 90 100 110 120 130 140 150 160 



Standard length V;ma 



Figure 5 



Relationship between standard length and combined-testes weight in 

 immature (open boxes), pubertal (filled boxes), and mature (triangles) 

 male franciscanas ^Pontoporia blainvillei) in Rio Grande do Sul (tt=79). 

 Data from pubertal animals are not included in the curves. 



testes weight (ANOVA, Fs=2.42; df=29; 

 P=0.76; /? = 30) between reproductive and 

 nonreproductive months. 



The analyses of the variation in the 

 diameter of the seminiferous tubules 

 throughout the year also did not indicate 

 that the testes undergo seasonal changes. 

 However, it is important to view this re- 

 sult with caution because the sample size 

 of mature males (and therefore the infor- 

 mation on tubules diameter collected in 

 reproductive months) was small (n=3). 

 However, the presence of spermatids or 

 spermatozoa (or both) in the seminiferous 

 tubules may be also regarded as a direct 

 evidence of testicular activity. Three ma- 

 ture males (119<-) in the sample presented 

 seminiferous tubules with spermatids or 

 spermatozoa (or both) and were collected 

 in nonreproductive months (May, June, 

 and August). Although the epididymis of 



