3 - 



Ui 



^2- 



^ 



0-3 DAYS OUT 



AUGUST 10 

 EA-45 



uj 100 I I I VOO 100 I 



1-1 - 



ai 



^, 

 in 



UJ 



cn 



UJ 



> 



o 



u 



LU 



on 



LU 

 CQ 



5 



Z 



4-6 DAYS OUT 



7-10 DAYS OUT 



11-13 DAYS OUT 



I I VOO 100 I I I 100 



3 - 



AUGUST 16 EA-45 



100 



CS 



I I 100 100 



Lcs'fs'sp' 



CS 



I 

 'LCS' FS 



100 



SP' CS ' 



MILES FROM TRAP SITE 



■lcs'fs' 



SP' 



100 



CS 



J I 100 

 "LCSFS'SP' 



Figure 14.— Tag recoveries per trap per time period by 20-inile intervals measured from the point of release in lower Chatham 



Strait, 1941. 



migration. Both types of data show two main migra- 

 tion routes, one starting in Icy Strait and leading 

 south through upper and middle Chatham Strait into 

 Frederick Sound and the other leading from lower 

 Chatham Strait into Frederick Sound. In Figures 16 

 to 20, the weekly catch per trap is plotted against time 

 in weeks for the major statistical subareas for the 

 years 1938-42. Lynn Canal is included with upper 

 Chatham Strait. The vertical lines represent the 

 dates, obtained by linear interpolation, at which the 

 catches per trap were 10,000 and 20,000 fish per week. 

 The time difference in days between the 10,000- and 



20,000-fish-per-week levels in outer Icy Strait and four 

 inner areas is given in Table 12. The catch per trap 

 during the seventh week in inner Icy Strait in 1938 

 reached 19,806 but not 20,000 and, although omitted 

 from Figure 16, the time difference was calculated and 

 is given in Table 12. Table 13 lists time differences 

 between lower Chatham Strait and two inner areas. 

 In all years, the average catch increased first in out- 

 er Icy Strait and then in inner Icy Strait, upper 

 Chatham Strait, and middle Chatham Strait in that 

 order, as would be expected if the fish were entering 

 through Icy Strait and moving south. Since traps in 



100 



Ilcs' fs'sp' 

 from trap site 



Figure 15. — Tag recoveries per trap per time period by 20-mile intervals measured from the point of release in lower 



Chatham Strait, 1942. 



25 



