NOTE Cope Intraspecific life history patterns in sharks 



315 



Age at maturity 



Longevity 



-0 2- 



-0.6- 



-1.0 



-0.2 



-0.6 



-1.0 



NP NoA GM I 



Fecundity 



CP 



NP NoA GM I CP SP SA 



D 



?, -0.1 



-0.3 



-0.5 



000 

 -0.05 



-0.15- 



Size at maturity 



NP NoA GM I CP SP SA 



NP NoA GM I CP SP SA 



E 



IVlaximum size 



-0.05 



-0.15 



NP NoA GM 



CP SP SA 



Figure 2 



Bar plots of the area effects for each life history trait. Areas: NP=North Pacific; NoA=North Atlantic; 

 GM = Gulf of Mexico; Ulndian Ocean; CP=Central Pacific; SP=South Pacific; SA = South Atlantic. 

 Vertical bars represent one standard deviation. The North Pacific area is the reference area, and 

 all other areas are standardized to it. To interpret the relationships, lower effect values in relation 

 to effect values from another area indicate the life history trait value would also be lower. 



larger, to mature later in life, to have longer life spans, 

 and to have greater fecundity compared to conspecifics 

 in the central and southern latitudes. Populations in 

 the North Pacific, in particular, seem to demonstrate 

 dramatic departures in life history measures compared 

 to conspecifics in other areas. Therefore, instead of as- 

 suming life history information from one region should 

 be applied to another region, the trends and predictive 

 methods offered in the present study provide a means to 

 extrapolate life history traits of cosmopolitan species in 

 specific areas when only information from other areas 

 is available; this method may prove useful for develop- 

 ing informative priors for Bayesian analyses (Punt and 

 Hilborn, 1997). Caveats to these results include area- 

 specific biases (i.e., certain-size individuals susceptible 



to capture) and errors in sampling programs and migra- 

 tory patterns of specific species (e.g., individuals may be 

 found in multiple areas during different parts of their 

 life history). Thus a proper knowledge of the biology 

 of the species is recommended before interpreting the 

 interpolated life history values. 



Other factors, such as fishing pressure, may influence 

 regional differences in life history traits, challenging 

 the interpretation of such patterns. Truncation of size 

 and age classes, and reduction in age at maturity are 

 recognized byproducts of heavy fishing (Longhurst, 

 1998a; Rochet, 2000). Although all the populations 

 used in this study are and have been fished — some 

 more intensely than others — this study assumes there 

 is no consistent pattern to such exploitation in shark 



