NOTE Pearson Timing of hyaline-zone formation in otoliths of Sebastes entomelas 



191 



nia (lat. 40° to 42°N) and throughout the coast of 

 Washington (lat. 46° to 49°N). 



Otoliths were examined only from fish less than 

 45 cm fork length because it is seldom possible to 

 determine reliably the edge type of older, larger fish. 

 On the basis of age-length relationships developed 

 by Pearson and Hightower ( 1991 ), these fish ranged 

 between four and twelve years. The dates of capture 

 were not provided to the age reader; however, the 

 reader did know the source (state) from which the 

 otoliths were collected. The otoliths were broken and 

 burnt according to the methods described by Chilton 

 and Beamish (1982) and examined with reflected 

 light with a dissecting microscope (20-30x). Edge 

 types were classified as hyaline, narrow opaque 

 (opaque area less than 1/2 of the previous opaque 

 zone), and wide opaque (opaque area greater than 1/2 

 of the previous opaque zone). In about 1% of the fish 

 (older fish), the edge could not be clearly identified 

 owing to the narrowness of the rings. In this situa- 

 tion the otolith was omitted from the analysis. An 

 attempt was made to obtain edge types of otoliths 

 from 100 fish per month, per year, per state, but this 



was not possible in many cases (Table 1). A total of 

 approximately 10,230 otoliths were initially exam- 

 ined, and edge types were ultimately determined for 

 6,384 fish. 



The purpose of this study was to examine the tim- 

 ing of hyaline-zone formation. More than 95% of all 

 otoliths had formed new opaque zones by July, and 

 because sample sizes were small and patchy for Au- 

 gust through December, these samples were not tested. 



As some edge types were rare in certain months, 

 edge types were omitted from some of the monthly 

 analyses for both states as follows. When fewer than 

 three otoliths had a given edge type, and when the 

 edge type was uncharacteristic for that month, the 

 otoliths were removed from the analysis. In January 

 and February, narrow opaque edges were omitted; 

 in April and May, wide opaque edges were omitted; 

 and in July, hyaline edge types were omitted. 



To determine whether significant differences in 

 edge type existed between sexes, locations, and years, 

 multiway contingency tables were examined by chi- 

 square analysis with the CATMOD procedure, which 

 has the log-linear option, in the SAS statistical analy- 



