I I I II I I I I I I I I 



Figure 3. --Daily river discharge. Rock Island Dam, 

 May 2 to October 29, 1960. 



There were no dewaterings necessary of 

 middle and right bank fishways during 1960. 

 The left bank fishway was dewatered twice 

 as follows: (1) April 28, to install special 

 weir for electronic fish counting experiments; 

 and (2) November 11 and 12, to remove special 

 weir. 



Electronic fish counting experiments began 

 on July 21 and continued through August 5. 



Broken guide rails prevented operation of 

 crest gate number 37, thereby eliminating 

 use of this gate to add attraction flow near 

 the right bank ladder. 



In 1960, six chinook and one sockeye salmon 

 bearing Fish Commission of Oregon colored 

 tags were recorded through the fishways at 

 Rock Island Dam. 



SUMMARY 



1. Total count of salmon and steelhead 

 trout at Rock Island Dam was 93,211 in 1960. 

 This was less than the 1959 count of 99,959 

 but exceeded the 27-year mean of 70,983. 



2. Yearly total counts of salmon and steel- 

 head trout passing Rock Island Dam during 

 the period 1933-60, inclusive, are given in 

 table 1. 



3. The chinook salmon count of 26,550 in 

 1960 exceeded the total for this species in 



1959 and was slightly greater than half the 

 peak year of 1957. In 1960, 5,082 jacks were 

 recorded, representing 19.1 percent of that 

 year's count. 



4. The sockeye salmon count of 60,341 in 



1960 was less than in 1959 but exceeded the 

 27-year mean of 52,824. Small sockeye under 

 16 inches in length comprised 10.5 percent 

 of the run. A greater percentage of sockeye 

 utilized the left bank ladder than used either 

 the middle or right bank ladders. 



5. Few coho salmon have appeared at Rock 

 Island Dam in the period 1933-60. Greatest 

 count of this species of salmon occurred in 

 1947, when 229 fish were recorded. The 1960 

 count of 94 was less than that of 1959 but 

 exceeded the 27-year mean of 60. 



6. The steelhead trout count of 6,226 in 

 1960 exceeded all previous records and was 

 well above the 27-year mean of 2,946. 



7. Although no quantitative data are avail- 

 able, it was the impression of the fishway 

 superintendent and the counters that the inci- 

 dence of injured fish was probably less than 

 half that observed in 1959. 



8. Fish other than salmon and steelhead 

 trout passing Rock Island Dam in 1960 totalled 

 approximately 150,660. 



9. Fish counting was begun on May 2 and 

 ended October 29. 



10. Maximum number of salmonids counted 

 in 1 day during the 1960 season was 3,574 on 

 July 19. 



