180 



Fishery Bulletin 101(1) 



34 36 38 40 42 44 



Length (cm) 



48 



50 



Figure 6 



Length-gonadosomatic index (GSI) relationship for darkblotched rockfish iSehastes cramcri). 



ten difficult for the older, more difficult-to-age individuals 

 but can be accompli.shed by using a variety of techniques 

 ranging from marking to analysis of radioactive isotopes 

 (Lai et al., 1996). The estimate of longevity is also depen- 

 dent on sample size and previous fishing history Hoenig 

 (1983) showed that maximum age tends to increase slowly 

 with increasing sample size after about 200 individuals 

 have been examined, but longevity has probably declined 



from historical levels because of fishing, particularly in the 

 case of the darkblotched rockfish. A small sample size for 

 age determination, underaging, and previous exploitation 

 would all result in an overestimate of M with Hoenig's 

 method and might explain some of the difference between 

 the estimate of arrowtooth flounder mortality based on 

 reproductive effort or K (M=0.08-0.11) and the previous 

 estimate (M=0. 18). 



