Table 1. — 1Q57 fishway rapacity test summary. Number and percentage of fish passed, 

 passage time—', and species composition. All tests for 60-minute duration. 



_!/ Time required to ascend 6 pools. 



2/ Free release (no brail used in collection pool area). 



3/ The discrepancy of 6 fish (more leaving than entering) was due to count error. 



Table 2. --Number of fish available for passage and related entry and exit 

 in five fishway capacity trials, 1957. 



u m b e r of fish 



Test 



Estimated weight in pounds 



Total High average High average Average Total Maximum 



available Maximum Maximum entry/mm. exit/min, weight available entry i./ 



for entry exit 20-minute 20-minute per for Total per 



Date passage per min. per min. period period fish passage entered minute 



40 

 31 

 85 

 30 

 30 



42 

 34 

 64 

 24 

 26 



28 

 25 

 50 

 20 



21 



1/ Based on average of the maximum number entering in a 3-minute period. 



Rate of ascent may be expressed in 

 terms of pools per hour or as vertical ascent 

 in feet per minute. In these tests, which 

 apply to a 6-pool fishway having an overall 

 rise of 6 feet (excluding the initial 1-foot 

 rise into the fishway), a simple division 

 of passage time by 6 will give the mecin time 

 per pool. Vertical ascent in feet per min- 

 ute may be obtained by dividing the height 

 ascended (6 feet) by the passage time. Thus, 

 if the mean passage time for 6 pools is 12 

 minutes, the rate of ascent becomes 30 pools 

 an hour (1 pool every 2 minutes), the verti- 

 cal rise 1/2 foot per minute. 



Average Size Determination 



A specific measure of fishway capacity 

 must consider the average size of the fish 

 passed. Obviously, any estimate of maximum 



passage per unit time will have little mean- 

 ing unless it is further qualified in terms 

 of a unit measure of fish size. While the 

 average displacement per fish may be the most 

 desirable measure of fish size, the physical 

 handling which would be necessary to obtain 

 such a determination is readily apparent. 



In these tests estimates of the aver- 

 age length of each species were obtained 

 from Scunple observations as the fish entered 

 the collection pool. Estimated lengths were 

 converted to pounds and applied as a unit of 

 average fish size in the different trials. 

 Seasonal length-weight relationships for 

 Chinook salmon ( Oncorhynchus tshawytscha ) 

 during 1957 were kindly provided by the Ore- 

 gon and Washington state fisheries depart- 

 ments. Appendix table A-1 gives these data 

 for the period April 30 to August 25. 



