Table 1. — Stream survey and Eock Island Dam counts of spring and summer 



Chinook, 1956-57 



''" The week ending June 25 was the division date separating spring and summer Chi- 

 nook; the week ending August 27 was the division date for summer and fall chinook. 

 2 In 1956 overlap of runs precluded separation of sprine and siimmer chinook. 



20,000 



19,000 ■ 



1 8,000 



17,000 



16,000- 



15,000 - 



14,000 



13,000 



^ 12,000 

 to 



^ 11,000- 

 o 10,000 



tr 

 111 

 m 



9000 

 8000 

 7000 

 6000 

 5000 

 4000 

 3000 

 2000 

 1000 





I ; V 



1954 91.234 



1955 155.055 



1956 92,443 



1957 71,261 



15 20 

 JULY 



15 20 

 AUGUST 



Figure 3.--Blueback salmon counts at Rock Island Dam. 1954-57. 



5 



