In the absence of specific length- 

 weight data for species other than chinook 

 salmon, ain estimated average poundage was 

 assigned for each on the basis of visual 

 observation. Steelhead ( Salmo gairdneri ) 

 were estimated at 6 pounds and blueback 

 salmon (0. nerka ) at 2.5 pounds. Other 

 species, including suckers ( Catostomus sp.), 

 squawfish ( Ptychocheilus oregonensis ) , carp 

 ( Cyprinus carpio ) and chubs (Acrocheilus 

 alutaceus ) were summarily estimated to 

 average 1 pound. 



in the May 8 trial when a rather high 

 percentage of jacksl''^ appeared in the run, 

 materially reducing the average size of 

 chinook salmon in this test. 



Total numbers entering the test fish- 

 way during the 60-minute test periods ranged 

 from 619 to 1,647 fish, or approximately 

 6,000 to 17,000 pounds, in the five trials. 

 In the discussion, particular emphasis is 

 placed on the May 1 and June 25 tests. 



Maximum Entry and Exit 



RESULTS 



Review of 1957 Fishway 

 Capacity Trials 



Five f ishway-capacity trials conducted 

 during 1957 are summarized in tables 1 and 2. 

 The trials of May 1 and May 8 used chiefly 

 spring-run chinook salmon, while the three 

 tests on June 25 include 

 mer-run chinook salmon— 

 and steelhead trout. 



id a mixture of sum- 

 blueback salmon. 



Differences in aversige estimated 

 weights of fish in the various trials (table 

 2) may be explained mainly by differences in 

 species composition (table 1). Generally, 

 chinook salmon were the largest of all spe- 

 cies tested. An exception to this occurred 



10 20 30 40 



Elapsed time in minutes 



Figure 5. — Observed entry and exit during 60-niinute 

 capacity trial on May 1, 1957. Chinook salmon 

 (O. tshawytsclia ) averaging 14 pounds were the 

 predominant species. 



Table 2 gives the maximum numbers 

 observed to enter and leave the test fishway 

 per minute. Graphic presentation of the 

 60-minute entry and exit observed in tests 

 1 and 3 is shown in figures 5 and 6. (Fur- 

 ther data on observed counts in all tests 

 may be found in table A-2). For fish 

 (predominantly spring chinook) averaging 14 

 pounds, the maximum entry was 61 fish a 

 minute. This compares with a maximum 

 observed entry of 75 fish a minute during a 

 1956 trial (filling and Raymond, 1959) when 

 fish (predominantly fsill chinook) averaged 

 13 pounds and the fishway wjis 6 feet wide. 



20 30 40 



Elopsed time in minutes 



Figure 6. — Observed entry and exit during test No. 3 (June 25, 

 1957) . Fish passed were a mixture of chinook salmon (O. 

 tshawvtscha ). blueback salmon (O. nerka ) and steelhead 

 trout (S^. gairdneri) . The average estimated weight was 

 9.2 pounds. 



3/ Columbia River chinook salmon runs have been arbitrarily 

 divided into spring, siunmer, and fall migrations with the 

 the respective periods ending on May 31, August 15, and 

 December 31. 



4/ The term "jack" salmon on the Columbia River generally 

 applies to a mature male chinook salmon returning up- 

 stream after one year or less ocean residence. While 

 several size distinctions are in use, in these experiments 

 all chinook salmon 20 inches and under were ubitrarily 

 classified as jacks. 



