160 



Fishery Bulletin 103(1) 



information provided in our study indicates that our 

 aging criteria for Pacific cod are roughly correct and 

 that errors are probably within plus or minus 1 or 2 

 years. However, the problem of the shift in length at 

 age alluded to in the introduction is more difficult to 

 elucidate. Analysis made during this study seems to 

 indicate that both environmental growth factors and 

 changes in otolith aging criteria could have played a 

 role in this apparent shift. 



Acknowledgments 



This work was performed in partial fulfillment of the 

 requirements for an M.S. degree at the School of Aquatic 

 and Fishery Sciences at the University of Washington 

 and was supported by the National Marine Fisheries 

 Service. We would like to express our appreciation to 

 those individuals who assisted in the tagging and recap- 

 ture process and to the two anonymous reviewers for 

 their helpful comments on the manuscript. 



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