Annual Fish Passage Report - Rock Island 

 Dam Columbia River, Washington, 1964 



By 



PAUL D. ZIMMER and JOHN H. BROUGHTON 



ABSTRACT 



Fish using the three fishways at Rock Island Dam in 1964 were counted from 

 May 1 to October 24. The total number of salmon and steelhead trout exceeded the 

 1963 count by 7,885 fish. 



The 1964 count of 39,951 chinook salmon was more than twice the mean of 

 17,355 for the 31 -year period 1933-63 and exceeded the 1963 count by 5,263 fish. 

 The 69,411 sockeye salmon counted was 4,643 more than recorded in 1963 and 

 exceeded the 31 -year mean of 51,603. The 61 coho salmon counted was about 75 

 percent of the 31 -year mean of 81 and 8 percent of the record count of 737 in 1962. 

 The 5,016 steelhead trout count in 1964 was well above the 31-year mean of 3,457 

 and 2,062 less than in 1963. Fish other than salmon and steelhead trout passing 

 through the fishways at Rock Island Dam in 1964 numbered 118,284 and exceeded the 

 count of salmon and steelhead trout by 3,845 fish. 



Of the 114,439 salmon and steelhead trout observed at Rock Island Dam in 1964, 

 about 2 percent had visible evidence of injury about the head or body. 



INTRODUCTION 



Rock Island Dam, located on the Columbia 

 River about 12 miles downstream from We- 

 natchee, Wash., has been in operation since 

 1933. The plant is owned and operated by 

 Chelan County Public Utility District No. 1. 



This report on passage of fish at Rock 

 Island Dam during 1964 provides information 

 on operations of fishways and numbers of 

 fish using them. 



Rock Island Dam has three fishways: one 

 located on the right bank, another on the left 

 bank, and the third about the center of the 

 dam. The bank fish ladders began operating 

 in 1933, and the middle ladder in 1936. All 

 three ladders have been modified since then. 



Fish ascending Rock Island Dam ladders 

 have been counted annually since 1933, the 

 longest continuous record of Columbia River 

 fish counts. 



Included in this report are comments cov- 

 ering various fishery investigations at Rock 

 Island Dam during 1964. 



COUNTING PROCEDURES 



Fish counting in 1964 began on May 1 and 

 ended October 24. From May 1 through 

 August 31, fish were counted 16 hours each 



Note. — Paul D. Zlmmer, Fishery Biologist (Manage- 

 ment), and John H. Broughton, Fishery Technician, Bureau 

 of Commercial Fisheries Program Office, Portland, Oreg. 



day, starting at 5 a.m. and ending at 9 p.m. 

 From September 1 through October 10, counting 

 was reduced to 14 hours each day, starting at 

 6 a.m. and ending at 8 p.m. to conform with 

 the available daylight. From October 11 to 

 October 24, fish counting was reduced to one 

 shift each day from 8 a.m. to 4:30 p.m. 



Fish counters were alloweda 15-minute rest 

 period at the end of each hour. During all 

 periods of noncounting, ladders were closed 

 to fish. 



A water glass was floated on the surface 

 over each counting board to eliminate sunglare 

 and water surface disturbances and thus permit 

 clear observation of each fish. 



ENUMERATION OF FISH 



All species of fish using the fishways at 

 Rock Island Dam are identified and recorded. 

 Because of their greater importance, special 

 mention is made of the different species of 

 salmon and of the steelhead trout passing the 

 dam, and each is discussed separately. 



Chinook Salmon, Oncorhynchus tshawytscha 



The 1964 chinook salmon count of 39,951 

 (jacks included) was more than twice the mean 

 of 17,355 for the 31-year period 1933-63. It 

 was also greater than the 1963 count and about 

 79 percent of the record count of 50,713 in 

 1957 (table 1). Monthly totals of chinook salmon 

 given in table 2 show a peak movement of these 



