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Fishery Bulletin 94(1), 1996 



ton than in those from fish in California. In addi- 

 tion, there are annual differences in the timing of 

 hyaline-edge formation. Problems in age determina- 

 tion may arise when the forming annulus is small 

 relative to preceding annuli. In this case, a fish col- 

 lected in March might be mistakenly aged as one- 

 year younger. This would occur because the reader 

 might consider the completed opaque zone to be new 

 growth for the current year. This problem is more 

 likely to occur in young fish where the relative size 

 of the annuli is comparatively large. 



The later time of hyaline-zone formation in 1983 

 (Fig. 2) suggests a possible explanation for the ob- 

 servation that the opaque zone formed that year was 

 smaller than those formed in preceding and subse- 

 quent years (Woodbury 3 ). As the opaque zone formed 

 later in 1983, particularly in California ( Fig. 2 ), there 

 was less time for the opaque zone to form, and there- 

 fore a smaller opaque zone was visible for that year. 



3 Woodbury, D. P. 1994. National Marine Fisheries Service, 

 3150 Paradise Drive, Tiburon, CA 94920. Unpubl. data. 



