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Fishery Bulletin 100(2) 



Figure 3 



Vertebral sections from recaptures of three known-age porbeagles and one OTC-injected porbeagle. 

 Annuli are indicated, as is the birth mark. Scale bar = 1 mm. 



a mean length of 85 cm FL and grew to a mean length 

 of 98 cm FL by December. Age-1 individuals had a mean 

 length of 106 cm FL in April. 113 cm FL in July, and 123 

 cm FL in December, resulting in an annual growth of 25 

 cm/yr between December and December. Although larger 

 length modes were occasionally visible, only the age-0 and 

 age-1 modes were clear and unambiguous throughout the 

 year. 



The MULTIFAN models that best fitted the 1991 data 

 were the most complex, having variable standard devia- 

 tions in length and variable seasonal growth. The data 

 with sexes combined had 18 age classes, whereas males 

 and females had 16 and 15 age classes, respectively. The 

 MULTIFAN L . and A' von Bertalanffy parameters fell out- 

 side the 95% confidence intei-vals for the tagging and ver- 

 tebral studies, although the tg values did not (Table 2). 



These differences are reflected in the VBGF curves as com- 

 pared with the other methods (Fig. 8). The annual growth 

 rate calculated from the MLILTIFAN data was consistent 

 with that of the vertebral and tag-recapture analyses at 

 150 cm FL (Fig 6). However, the reliability of the MULTI- 

 FAN results is questionable given the large number of age 

 classes in the population. The standard error estimates 

 calculated by MLILTIFAN were not reported because they 

 were unrealistically low (Francis and Francis, 1992; Fran- 

 cis and Mulligan, 1998). 



Longevity 



The maxmium ages based on vertebral band pair counts 

 were 25 and 24 years for males and females, respectively. 

 These ages likely underestimate longevity, given the long- 



