WITH CONE 

 WITHOUT CONE 



100 



SOCKEYE STEELHEAO 

 SALMON TROUT 



SPRING SUMMER 

 CHINOOK CHINOOK 

 SALMON SALMON 



Figure t). — Percentages ot Chinook salmon, sockeye salmon, 

 and steelhead trout that completed passage through the 

 introductory pool of the 0.3-m. -diameter pipe with and 

 without the truncated entrance cone, 1964. 



a series of tests was made in the 0.6-m.-diam. 

 eter pipe. Chinook, sockeye, and coho salmon 

 and steelhead trout were tested. 



Passage times . --Passage time through the 

 82,3 m. length of 0.6-m. -diameter pipe (A to 

 B, fig. 5) was used to measure the influence of 

 illumination on fish passage. Water velocity 

 was 0.9 m.p.s. 



Passage was generally faster in the illumi- 

 nated than in the nonilluminated pipe (table 8). 

 Median passage times of fall chinook salmon 

 and steelhead trout were significantly less when 

 the pipe was illuminated than when it was not 

 (5.5 and 9.9 minutes, and 7.0 and 24.4 minutes, 

 respectively). Sockeye and coho salmon also 

 passed through the illuminated pipe faster 

 than through the nonilluminated pipe, but the 

 difference between the median passage times 

 of each species under the two conditions was 

 not significant. In contrast, the median passage 

 time of summer chinook was greater in the 

 illuminated pipe (11.8 minutes) than in the 

 nonilluminated pipe (8.1 minutes); this dif- 

 ference, however, was not statistically signifi- 

 cant. No reason can be given for the signifi- 

 cant difference in passage times between 

 summer and fall chinook salmon through the 

 illuminated pipe. 



Additional tests of the illuminated versus 

 nonilluminated pipes were made to determine 

 the influence of depth of flow on fish passage 

 (discussed later). Water velocity was also 0.9 

 m.p.s. in these tests, but the pipe was only 

 partly filled. 



Median passage time of fall chinook salmon 

 (table 9) was significantly less in the illumi- 

 nated than in the nonilluminated pipe (5.5 and 

 15.4 minutes, respectively). Coho salmon also 

 moved through the pipe faster under illumina- 

 tion than without (4.8 and 13.1 minutes, re- 

 spectively); the small sample size under 

 illumination, however, precludes testing for 

 statistical significance of the difference in 

 passage times. 



The response of fall chinook and coho salmon 

 to illumination and nonillumination in a partly 

 full pipe were in general agreement with their 

 response to these same conditions in a full pipe. 



Percentages of fish that completed 

 pas sage . --Per cent ages of fish in flooded pipes, 

 0.6-m. -diameter, that completed passage under 

 illuminated and nonilluminated conditions 

 varied considerably by species (fig. 7). A higher 

 percentage of steelhead trout completed pas- 

 sage when the pipe was illuminated than when 

 it was not (98 and 55 percent, respectively). In 

 tests of summer chinook and coho salmon, 

 however, the situation was reversed-.higher 

 percentages completed passage when the pipe 

 was not illuminated than when it was (95 and 

 76 percent, 97 and 76 percent, respectively). 

 About 97 percent of the fall chinook and sock- 

 eye salmon completed passage, whether the 

 pipe was illuminated or not. 



When the 0.6-m. pipe was partly flooded, 

 higher percentages of fall chinook and coho 

 salmon completed passage through the illumi- 

 nated pipe than through the nonilluminated pipe 

 (100 and 80 percent, and 100 and 86 percent, 

 respectively, fig. 7). It appears that illumina- 

 tion influences these fish more in a partly 

 filled than in a completely flooded pipe. 



Sharp Turns in the Pipe 



Response of salmon and trout to 180° turns 

 in the pipe when illuminated and when non- 

 illuminated was evaluated during passage 

 through five sections of a 0.6-m. -diameter 

 pipe, 82.3 m. long. Six electronic detectors 

 recorded the passage times through each of 

 the three straight sections and the two 18CP 

 turns which made up the pipe system (fig. 5). 

 This information was collected incidentally 

 during studies on the effect of light on fish 

 passage at a water velocity of 0.9 m.p.s., 

 from June to September 1964. Only fish for 

 which we had a complete sequence of passage 

 times through all five test sections of pipe 

 were used. 



Comparison of the rates of passage through 

 the sections (fig. 8) under the illuminated and 

 nonilluminated conditions illustrates that the 



11 



