46 



Fishery Bulletin 103(1) 



- 1 r- 



Apr 30 May 20 Jun 9 Jun 29 Jul 19 Aug 8 Aug 28 Sep 17 Oct 7 Oct 27 



0065 



060 



0.045 



& 0.040 - 



ro 0.035 - 



0.030 



B 



Maturing fish 



Apr 30 May 20 Jun 9 Jun 29 Jul! 9 Aug 8 Aug 28 Sep 17 Oct 7 Oct 27 



□ 

 A 



Maturing fish 



$ 2 

 o 





Apr 30 May 20 Jun 9 Jun 29 Jul 19 Aug 8 Aug 28 Sep 17 Oct 7 Oct 27 



Date 



Figure 7 



Average spacing of the last two intercircular spaces at the scale margin versus 

 average catch date for (Al juvenile coho salmon (O. kisutch) caught during research 

 cruises and (B) maturing coho salmon caught during research cruises (gray and 

 white symbols) and in the ocean fisheries (black symbols, averaged by 10-day 

 periods, all years combined). Also shown for comparison with the temporal changes 

 in circulus spacing are (C) the apparent growth rates of maturing coho salmon 

 between research cruises (based on changes in mean FL; see Fig. 6) plotted against 

 the mid-point of each growth period. 



based on data in Ishida et al. (1998). Therefore, the 

 roughly twofold range in spacing of circuli in the ocean 

 growth zone of scales from maturing fish that we found 

 probably represents about a fourfold range in fish growth 



rate in the ocean (from about 0.5 mm/d in the winter to 

 2.1mm/d in the spring and early summer). Thus, changes 

 in the spacing of scale circuli are relatively small when 

 compared to the corresponding changes in fish growth 



