or dislodgment from the gravel by high water- - 

 the dead alevins were still present. Poor 

 water circulation within the spawning bed 

 in the lower area, which has a low gradient 

 and relatively fine particles, may have pro- 

 duced weak alevins that had a lowered sur- 

 vival rate during winter. 



The high survival throughout the streann in 

 period 4 (fry emergence and nnigration) indi- 

 cates that predation was not severe during 

 this period. 



The number of viable pink salmon eggs 

 of the 1963 brood year declined from about 

 16.8 million to about 5.6 million between 

 the beginning and the end of spawning. Mor- 

 tality in autumn, winter, and spring further 

 reduced the number to 3.2 nnillion fry mi- 

 grating to sea. Total fresh-water survival 

 was estimated to be 31 percent in the upper 

 area, 16 percent in the nniddle area, and 

 15 percent in the lower area (table 10). The 

 number of fry in spring 1964 was about 

 360/nn.^ in the upper area, 268/nn,2 in the 

 nniddle area, and 174/m.2 in the lower area. 



Table 13. — Survival of pink salmon from potential 

 for the 11 larger and 11 smaller 



Merrell (1962) also observed a considerably 

 higher density of fry of the 1959 brood year 

 in the upper area (about 325/m.2) than in the 

 lower (about 135/nn.2). 



In 2 years of high abxindance (1959 and 

 1963), spawning pink salmon were concen- 

 trated in the middle area, whereas in 2 

 years of low abundance (1958 and 1964), 

 they were concentrated in the lower area. 

 In 1959 when 35,391 fish migrated upstream, 

 the density of spawners was at least twice 

 as high in the middle area as in the other 

 two areas. In 1958 when only 217 spawning 

 fish entered the creek, they concentrated 

 in the lower and middle areas (Merrell, 1962); 

 in 1964 when 2,200 fish were counted, I ob- 

 served the highest density of spawners in 

 the lower area and alnnost no spawners in 

 the upper area. 



Little is known of the factors that cause 

 pink salmon to select particular sites for 

 spawning. Fabricius and Gustafson (1954) found 

 that char demonstrated a preference for ma- 

 terial of certain sizes in the spawning bed. In 



egg deposition to migrant fry in Sashin Creek 

 of 22 escapements, 1940-63^ 



■"■ No fish were allowed to spawn in 1952 and 1960. 



10 



