Wintner and Cliff: Age and growth determination of Carcharodon carcharias 



161 



■a 



•o 



400 



350 



300 - 



250 - 



200 



100- 



50- 



-SC-A 

 XR-A 



5 6 7 8 



Number of growth rings 



10 



12 



13 



14 



Figure 6 



Von Bertalanffy growth curves and parameters for the white shark, C. carcharias, sexes combined. Growth ring estimates 

 were obtained by using methods SC-A and XR-A. Observed values { + ) are those for the method SC-A. Squares indicate 

 shark BT433 at tagging and recapture. 



method XR-A. For these rea- 

 sons the results of the former 

 method were used for back- 

 calculations, MIR analysis, fit- 

 ting of the Gompertz growth 

 curve, growth calculations, 

 and GR estimates. 



Table 7 shows the number 

 of GRs counted for various 

 animals. The largest female, 

 an adolescent, (297 cm) had 

 6 GRs; there were no mature 

 females. Of the three mature 

 males, the smallest had 8 



GRs (293 cm), the other two had 10 and 13 GRs (317 

 and 373 cm), respectively. Size at birth ranged be- 

 tween 100 cm (back-calculated value) and 135 cm 

 (predicted value). Shark BT433 was found to have 

 one GR at tagging ( 140 cm) and three GRs at recap- 

 ture (209 cm), after 2.6 yr at liberty (Fig. IB; Fig. 6). 



A Gompertz growth curve was fitted to the mass- 

 GR data ( Fig. 7 ). The female and male with the high- 

 est number of GRs, had 8 GRs (437 kg) and 13 GRs 

 (882 kg), respectively (Table 7). Mass at birth ranged 



between 22 kg (back-calculated value) and 54 kg (pre- 

 dicted value). 



Mean growth rates calculated from observed 

 lengths were higher overall than those calculated 

 from predicted lengths (Fig. 8). Mean growth for pre- 

 dicted lengths was 26 cm for the period 0-1 GR, de- 

 creasing to 20 cm (4-5 GRs), 16 cm (7-8 GRs), and 

 12 cm ( 12-13 GRs). Mean observed growth in mass 

 was also higher than that of predicted values (Fig. 

 8). Mean growth for predicted mass was 23 kg for 0- 



