In another trials, with a mixture of 

 Chinook and blueback salmon and steelhead 

 trout, the meiximum entry was 165 fish 

 per minute. These fish averaged 9.2 pounds. 

 The 20-minute high average entry was 64 

 fish per minute. 



2. Maximum observed exits applicable 

 to the above size groups (14 and 9.2 pounds 

 respectively) were 40 jind 85 fish per min- 

 ute. The high average exits for 20-minute 

 periods were 28 and 50 fish per minute re- 

 spectively for the two size groups. 



3. Total pounds of fish available in 

 the five tests ranged from 7,938 to 28,382. 

 Maximum entry in pounds (average of high 

 3-minute entry) ranged from 426 to 1,242. 

 A trend indicating increased entry with 

 increased availability was observed, but 

 additional tests, particularly with higher 

 levels of availability and during comparable 

 periods of the season, will be necessary to 

 establish the point at which a further 

 increase in fish available for passage fails 

 to produce an increase in the entry rate. 



4. The maximum number offish observed 

 in the first pool of the fishway was 178. 

 These fish (chinook, blueback, and steel- 

 head) averaged 9.2 pounds. On the basis of 

 total available space per pool (388 cu. ft.), 

 the average space per fish was 2.2 cubic 

 feet. Similarly for chinook salmon averag- 

 ing 14 pounds, the maximum number observed 

 in the first pool was 148 fish. This yields 

 an average space of 2.6 cubic feet per fish. 



6. Of all fallback activity, 91 

 percent occurred at the lower three weirs 

 of the fishway. The percentage of fallbacks 

 was independent of the number of fish enter- 

 ing the fishway, suggesting that other 

 factors may influence fallback activity. 



While the capacity of the test fishway 

 was not established in these trials, it is 

 believed to be in excess of 50 salmonids 

 (averaging 9.2 pounds) per minute. 



The limited number of trials, and the 

 differences in performance that may occur 

 between trials owing to season and species 

 composition, are factors to be considered 

 in evaluating the results of these tests. 



ACKNOWLEDGMENTS 



Dr. Gerald B. Collins assisted in the 

 planning jind development of this experiment. 

 The Biometrics Unit of the Seattle Biologi- 

 cal Laboratory provided helpful suggestions 

 on test procedures and the approach to the 

 determination of capacity. Mr. Milo C. Bell 

 reviewed the manuscript. 



Personnel assisting in these experi- 

 ments include J. R. Gauley, C. R. Weaver, 

 R. J. Holcomb, J. S. Johnson, K. L. Liscom, 

 D. L. Ellison, Louis Leonard, Marie Minkoff, 

 and Lucena Anderson. 



LITERATURE CITED 



5, The relation between rate of as- 

 cent and number of fish present in the fish- 

 way was examined in three trials conducted 

 on the same day. Results of these tests 

 suggest that crowding did not impede rate 

 of ascent. Maximum numbers of fish in the 

 fishway during the trials were 522, 236, 

 euid 308, and the respective rates of ascent 

 were 37.5, 35.3, and 33.3 pools per hour. 

 Minor differences in rate were believed to 

 be associated with species composition in 

 the tests rather than with the number of 

 fish present. 



ELLING, CARL H. , AND HOWARD L. RAYMOND 



1959. Fishway capacity experiment, 1956, 

 U. S. Fish and Wildlife Service, 

 Special Scientific Report — Fisher- 

 ies No. 299, 26 pp. 



LONG, CLIFFORD W. 



1959. Passage of salmonoids through a 

 darkened fishway. U. S. Fish 

 and Wildlife Service, Special 

 Scientific Report — Fisheries No. 

 300, 9 pp. 



MS #925 



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