11 12 13 14 15 

 520 I — \ — I — I 1 r 



OTOLITH LENGTH (mm) 

 16 



480 



E 



E 



- 440 



X 



I- 

 o 



2 400 



ILI 



o 



360 



320 



FEMALE 



-r 



17 



— r— 



280 I ^ ' ' I I I I I I 1 I I ' I I I I I L. 



3 5 7 9 11 13 15 17 19 21 23 



AGE (yr) 



Figure 3.— Age-length curve for widow rockfish, Sebastes ento- 

 vielas (from Lenarz 1987). The calculated total length from otolith 

 length is overlaid on the curve to obtain an estimate of age. 



should be used within well-defined limits. The 

 scattergram (Fig. 2) with the mean and range of 

 total length found at each 1 mm otolith length incre- 

 ment indicates the ranges within which these data 

 are useful. Some problems in relating otolith length 

 to age include the increased range of fish lengths 

 at older ages and the observed thickening-instead 

 of lengthening of otoliths in Sebastes (Boehlert 1985). 

 These results may be used to estimate total length 

 from an otolith length as shown in the following ex- 

 ample. If the otoliths are from fish of unknown sex, 

 the regression statistics from Table 3 would be used 

 to estimate fish length. If the otoliths are from fish 

 of known sex, Table 2 would be consulted. If a 

 species appears in Table 2, the regression statistics 

 for the appropriate sex would be used to estimate 

 fish length. If a species does not appear in Table 2, 

 Table 3 (with regression statistics for males and 

 females combined) would be used. For instance, to 

 estimate fish length from otolith length (OL) for 

 male S. auriculatus, the regression statistics from 

 Table 3 are used. An otolith 10.0 mm long gives an 

 estimated total length of 



TL = a + 6 (OL) 



TL = -53.032 + 33.159(10.0) 



TL = 279 mm. 



Tables have been constructed with the regression 

 statistics presented here. The table for each species 

 (and sex, where appropriate) represents otolith 

 lengths measured in millimeters and the correspond- 



ing estimated total length. These tables are avail- 

 able on request from the author. 



Acknowledgments 



I wish to thank Sharon Moreland for assistance 

 in measuring the otoliths, and David Woodbury and 

 Carol Reilly for editing the data and running the 

 computer programs. The reviews by George Boeh- 

 lert, Bill Barss, and an anonymous reviewer were 

 very helpful. 



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