294 



Fishery Bulletin 88(2). 1990 



Figure 6 



Birth month of 25 bottlenose dolphin calves captured off southern 

 Africa back-calculated from the width of the first dentinal growth- 

 layer-group. 



Figure 7 



Relationship between combined ovary mass and the total number 

 of ovarian scars for female bottlenose dolphins captured off south- 

 ern Africa. 



female had a corpus albicans measuring 10x8x8 mm 

 (index volume 640 mm'') and was lactating, indicating 

 she probably had a suckling calf. Extrapolation from 

 a regression of calf length on an index of largest cor- 

 pora volume, for mother-calf pairs (Fig. 9), suggests 

 that the calf would have been some 184 cm in length 

 or 18 months old (Figs. 3,4), implying that her first 



o 



80 



100 120 140 

 Mass (kg) 



160 180 



20 

 18 

 16 

 14 

 12 

 10 



8- 



6- 



4 



2 







140 160 



180 200 220 

 Length (cm) 



240 260 



Figure 8 



Increase in the number of ovarian scars with mass, age, and length 

 of female bottlenose dolphins captured off southern Africa. A linear 

 regression (no. ovarian scars = 0..58 - 0.29 x age) fitted to this rela- 

 tionship in postpubertal females is shown. 



ovulation and conception occurred at approximately 

 10. .5 years of age. 



