Annual Fish Passage Report - Rock Island Dam 

 Columbia River, Washington, 1965 



By 



PAUL D. ZIMMER, Fishery Biologist (Management) 



and 

 JOHN H. BROUGHTON, Biological Technician (Fisheries) 



Bureau of Commercial Fisheries Program Office 

 Portland, Oreg. 



ABSTRACT 



Fish were again counted through the fishways at Rock Islamd Dam, thus pro- 

 viding counts at this location of the 33d consecutive year. Chinook and sockeye 

 counts were down, and coho and steelhead coxints were up from 1964. The counts of 

 Chinook, coho, and steelhead were larger, and the count of sockeye smaller than 

 their respective averages for 1933-64. The count of salmon and steelhead was 

 exceeded by the count of other species. 



Four and one-half percent of the salmon and steelhead passing through the 

 counting gates had injuries. 



Daily maximum and n-iinimum water temperatures and daily average rate of 

 stream flow were recorded. 



INTRODUCTION 



Rock Island Dam, located on the Columbia 

 River about 12 miles downstream from 

 Wenatchee, Wash., has been in operation 

 since 1933, and is owned and operated by 

 Chelan County Public Utility District No. 1. 



This report on passage of fish at Rock 

 Island during 1965 provides information on 

 the operation of fishways and the 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 cover- 

 ing various fishery investigations at Rock 

 Island Dam during 1965. 



COUNTING PROCEDURES 



Fish counting in 1965 began on May 1 and 

 ended October 15. From May 1 through August 

 31, fish were counted 16 hr. (hours) each day, 

 starting at 5 a.m. smd ending at 9 p.m. From 

 September 1 through October 15, counting was 

 reduced to 14 hr. each day, starting at 6 a.m. 



and ending at 8 p.m. to conform to available 

 daylight. 



Fish counters were allowed a 15-min. (min- 

 ute) rest period at the end of each hour. Dur- 

 ing all periods of noncounting, the gate at the 

 counting station was closed, and upstream 

 movement of fish was stopped at this point. 



A water glass, floated on the surface over 

 each counting board, eliminated sun glare and 

 water surface disturbances and thus permitted 

 clear observation of each fish. 



COUNTING OF FISH 



All species of fish using the fishways at 

 Rock Island Dam are identified and recorded. 

 Because of their greater importance, the dif- 

 ferent species of salnnon and the steelhead 

 passing the dam are discussed separately. 



Chinook, Oncorhynchus tshawytscha 



The 1965 Chinook count of 36,407 (jacks in- 

 cluded) was more than twice the average of 

 18,061 for the 32-yr. (year) period 1933-64 

 and was about 72 percent of the record count 

 of 50,713 in 1957 (table 1). Monthly totals of 

 Chinook given in table 2 show a peak movement 

 of these fish in July. Maximum day's count of 

 Chinook (jacks excluded) was 500 on August 5 

 (table 3), as compared to 896 on May 5, 1964. 

 Of the Chinook (jacks excluded), about 75 



