Nalanson et a\ Age and growth of Lamnus nosus in the western North Atlantic 



273 



term fishery for this species. Taylor's (1958) method, the 

 age at which 95% of the L.. is reached, provided a value 

 of 26 years. However, more reahstic estimates of longev- 

 ity take advantage of estimated mortality rates. Given 

 M=0.10 (Campana et al.'), Hoenig's (1983) equation based 

 on multiple species resulted in a longevity estimate of 45 

 years. The estimate of Campana et al.^ was species-inde- 



pendent and was calculated by assuming a constant instan- 

 taneous rate of mortality = 0.10 in an unfished population. 

 The resulting longevity estimate was 46 years. Each of 

 these methods assumes that M is constant throughout the 

 lifetime of a fish, whereas in fact, it probably increases in 

 sexually mature or senescent fish. Any such increase would 

 result in a lower estimate of longevity. Based on prelim- 



