Wintner and Cliff: Age and growtfi determination of Carcharodon carcharias 



155 



3.32 cm 



Dorsal 

 diameter 



B 



^m 



3.70 cm 



^r^ 



OB 

 TB 

 OB 

 TB 



OB 



OTC location 



under UV light 

 TB 



Birth mark 



^ GR 

 Zl OR 



GR 



R.B84044 

 9/8/84 

 Female 

 191 cm 

 115kg 



Figure 1 



Inverted scanned images of x-radiographs of two white sharks. OB = opaque band, TB = translucent band. GR = growth ring. 



Dorsal 



Intermedialia 



Caudal 



Angle change 

 (=birth mart) 



Ventral 



Dorsal 



"birth 



diameter" 



Corpus 

 calcareum 



B 



Dorsal 



Ventral 



Figure 2 



Schematic drawings of a vertebra illustrating terms used in the text. 



Distances from focus 

 to outer edge of each 

 growth ring 



Dorsal 



centrum 



diameter 



The relationships between centrum diameter and 

 both shark length and mass were examined by com- 

 paring regression lines of both sexes with the proce- 

 dure of Zar (1974), which compares the slopes and 

 elevations with Student's f-tests. Significance levels 

 given in the text are the results of these tests. Outli- 

 ers were determined by using Statgraphics (STSC, 

 1991) and eliminated. 



The Dahl-Lea method of back-calculation (Car- 

 lander, 1969) was used, in which 



PCL, = CD, (PCLJCD^), 



where PCL, = length at GR t\ 



CD, - centrum diameter at GR t\ 



PCL^ - length at capture; and 



CD^ = centrum diameter at capture. 



The Monastyrsky method of back-calculation 

 (Bagenal and Tesch, 1978, cited by Francis, 1990) 

 was used to estimate mass at age, in which 



M, = iCD/CD/ M^, 



where M, = mass at GR t; 



