ANNUAL FISH PASSAGE REPORT - ROCK ISLAND DAM 

 COLUMBIA RIVER, WASHINGTON, 1962 



by 



Paul D. Zimmer, Fishery Biologist (Management) 

 and John H. Broughton, Fishery Technician 



ABSTRACT 



Fish using the three fishways at Rock Island Dam in 1962 were counted from 

 May 1 to October 27. Total number of salmon and steelhead trout exceeded the 1961 

 count by approximately 12,300 fish. 



The 1962 count of 34,154 chinook salmon was well above the mean of 16,178 

 for the 29- year period 1933-61 and exceeded the 1961 count by approximately 1,100 

 fish. The 29,253 sockeye salmon counted was approximately 10,000 more than re- 

 corded in 1961 and approximately 57 percent of the 29-year mean of 51,920. The 737 

 coho salmon were approximately 500 more than recorded in 1947, year of previous 

 high count, and greatly exceeded the 50 fish in 1961. The number of steelhead trout 

 passing Rock Island Dam in 1962 was the highest recorded since counting began in 

 1933 and was more than twice the 29-year mean of 3,189. Fish other than salmon 

 and steelhead trout passing through the fishways at Rock Island Dam in 1962 num- 

 bered 164,574 and exceeded the count of salmon and steelhead trout by approxi- 

 mately 93,000 fish. 



Of 71,735 salmon and steelhead trout observed at Rock Island Dam in 1962, 

 approximately 0.5 percent had some visible evidence of injury about the head or 

 body. 



INTRODUCTION Rock Island Dam is now equipped with 



This report on passage of fish at Rock three fishways: one located on the right bank, 



Island Dam during 1962 provides information another on the left bank ' and the third approxi- 



on operation of fishways and numbers of fish matel y in the center of the dam - Two of the 



utilizing upstream fish passage facilities. fish ladders were P laced in °P eration in 1933 > 



and the third (middle ladder) was constructed 



Rock Island Dam, located on the Columbia in 1935-36. All three ladders have undergone 



River approximately 12 miles downstream significant modifications since initial con- 



from the city of Wenatchee, Wash., has been struction. 



in operation since 1933. The plant is owned 



and operated by Chelan County Public Utility Fish have been counted at Rock Island Dam 



District No 1 annually since 1933 — the longest continuous 



* record in the Columbia River. 



Note.--Paul D. Zimmer and John H. Broughton, , 



Bureau of Commercial Fisheries Columbia Fisheries Included in this report are comments cover- 



Program Office. U.S. Fish and Wildlife Service. m S various fishery investigations at Rock 



Portland, Oreg. Island Dam during 1962. 



