SUMMARY 



1. The total Rock Island Dam count of 

 salmon and steelhead in 1964 was 114,439, 

 about 7,900 more than in 1963. 



2. The chinook salmon count of 39,951 

 (jacks included) was 5,263 more than in 

 1963, more than two-thirds the peak year of 

 1957, and exceeded the 31-year average by 

 about 22,600 fish. In 1964, 14,493 jacks were 

 recorded, representing about 36 percent of 

 that year's total chinook salmon counted. 

 In 1963, jacks represented about 56 percent 

 of the chinook run. 



3. The sockeye count of 69,411 in 1964 

 exceeded the 1963 count by 4,643 fish and 

 was 17,808 more than the 31-year mean of 

 51,603. 



4. The coho salmon count of 61 in 1964 

 was about 75 percent of the 31 -year mean 

 of 81 fish and slightly more than 8 per- 

 cent of the peak year 1962 when 737 were 

 counted. 



5. The steelhead count of 5,016 in 1964 

 was 2,062 less than the 1963 count and 1,559 

 more than the 31-year mean of 3,457. 



6. In 1964, as in previous years, a greater 

 percentage of salmon and steelhead used the 



left bank fish ladder than either of the other 

 ladders. 



7. Counting began May 1 and terminated 

 October 24. From May 1 through August 31, 

 counting was conducted 16 hours each day; 

 from September 1 through October 1 0, counting 

 was reduced to 14 hours each day, 6 a.m. to 

 8 p.m., to conform to hours of daylight avail- 

 able. From October 1 1 to 24, counting was 

 reduced to one shift per day, 8 a.m. to 4:30 

 p.m. 



8. In 1964, maximum number of salmonids 

 counted in one day (6,866) occurred onJuly27. 



9. Season's total fish other than salmon 

 and steelhead trout passing Rock Island Dam 

 in 1964 was 1 18, 284, composed of the following: 

 sucker, 84,729; squawfish, 16,854; whitefish, 

 6,515; chub, 7,868; carp, 621; lamprey, 1,611; 

 Dolly Varden and rainbow trout, 86. 



10. Of the 114,439 salmon and steelhead 

 examined, on the top and one side only as 

 they passed over the counting boards, as in 

 1963 about 2 percent had injuries of some 

 type either on the body or about the head. 

 Most injuries were observed in July and 

 August. Large chinook and sockeye salmon 

 suffered a higher rate of injury than small 

 chinook, steelhead, and coho. 



MS. =1457 



23 



3P0 S69 - 248 



