ANNUAL FISH PASSAGE REPORT - ROCK ISLAND DAM 

 COLUMBIA RIVER, WASHINGTON, 1960 



by 



Paul D. Zimmer, Clifton C. Davidson 

 Fishery Biologists (Management) 



ABSTRACT 



Important runs of salmon and steelhead trout pass Rock Island Dam on the 

 Columbia River. Annual records of fish movement past the dam are available from 

 1933. 



Count of 26,550 chinook salmon in 1960 is slightly more than half the peak year 

 of 1957. Sockeye salmon count of 60,341 exceeded the 27-year mean of 52,823. Only 

 94 coho salmon were recorded. Greatest count of coho salmon, 229, occurred in 1947. 

 Numbers of steelhead trout passing Rock Island Dam increased in 1960. The 27- year 

 mean of 2,946 steelhead trout was less than the 1960 count of 6,226. Approximately 

 150,660 fish other than salmon and steelhead trout passed Rock Island Dam in 1960. 



INTRODUCTION 



Rock Island Dam, located on the Columbia 

 River approximately 12 miles downstream 

 from the city of Wenatchee, 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 1960 provides information 

 on operation of fishways and numbers of fish 

 utilizing upstream fish passage facilities. 



Rock Island Dam is equipped with three 

 fishways: one located on the right bank, 



Note.--Paul D. Zimmer and Clifton C Davidson 

 (deceased), Bureau of Commercial Fisheries Columbia 

 Fisheries Program Office, U.S. Fish and Wildlife 

 Service, Portland, Ore. 



another on the left bank, and a third ap- 

 proximately in the center of the dam. 



Biological data secured at Rock Island 

 Dam are useful in management of the Colum- 

 bia River fishery resource and in planning 

 fish facilities at other dams. 



COUNTING PROCEDURES 



Counting of fish at Rock Island Dam in 

 1960 began on May 2 and ended October 29. 

 Counting was conducted on a full-time basis 

 throughout each day's period of daylight. 

 During the period May 2 to September 15 

 counts were made 16 hours each day; Sep- 

 tember 16-30, 12; and October 1-29, 8 hours 

 at right and middle ladders and 12 hours at 

 left bank fishway. A 15-minute rest period 

 was allowed each hour. During periods of 

 noncounting the three fishways were closed 

 to upstream movement of fish. 



