AUGUST 9 WE 2H 



100 I 

 FS ISP 



100 I 

 I FS 'SP IS I CS 



MILES FROM TRAP SITE 



J 



' FS 'SP 



Figure 7. — Tag recoveries per trap by 20-niile intervals measured from the point of release in upper Chatham 



Strait, 1941. 



first release was on 25 July and the last on 18 August. 

 The distributions of recoveries from all releases in- 

 dicate extensive milling of pink salmon in the eastern 

 end of Icy Strait and throughout upper and middle 

 Chatham Strait. The type of movement observed in 

 1942 is in direct contrast to that observed in 1941, 

 when the fish moved rapidly to the south. 



For the earlier experiments in 1942 the center of 

 density remained at the tagging station and there was 

 a slow diffusion in both directions. In the later 

 releases the closure of the fishing season in Icy Strait 

 restricted recoveries there. Nevertheless there was 

 only a slight shift of the center of density of the tags to 

 the south of the release point. Although there was 

 some movement of tagged fish into Frederick Sound 

 from releases in August, this movement was of a 

 secondary nature. The 1942 experiments did not show 

 any clear progression of centers of concentration to the 

 south and east in successive recovery periods as did 

 the 1941 experiments. 



Recoveries from the two experiments on opposite 

 sides of the channel on 18 August 1942 indicate that 

 fish tagged in the northwestern part of upper 

 Chatham Strait (at trap WE-24) had ceased moving 

 rapidly and were probably milling about near the 

 spawning streams, whereas a large pecentage of those 

 tagged to the south on the eastern shore (at trap WE- 

 43) were still moving actively through Chatham Strait 

 headed for the inner waters of Frederick Sound and 

 Stephens Passage. 



In summary, the results of the tagging experiments 

 conducted in upper Chatham Strait supported the 

 general movement patterns hypothesized above on 

 the basis of releases made in Icy Strait. In 1941, and to 

 a lesser extent in 1940, fish tagged in upper Chatham 

 Strait moved rapidly southward in Chatham Strait 

 and then dispersed into Frederick Sound. The most 

 dense concentrations of tagged fish remained in the 

 middle Chatham Strait area for the first 1 V2 wk after 

 release. In 1942, however, the fish tagged in upper 



16 



