Lorqe SteelheoO 

 * Smoll Sieelheod 



] Large Chinook 

 Smoll Chinook 



10 20 30 40 50 60 70 80 90 



10 20 30 40 50 60 70 80 90 

 Disfonce ( in f eet) negotioled in channel 



Large Sleelhead 



Smoll Sleelhead 



Lafqe Chinook 

 Small Chinook 



Responses of the nature indicated in lliesc tests 

 suggest the possibility that upstream migrating 

 salmonids may actually be diverted from fishway 

 entrance flows into those of the spillway or even 

 into the turbine discharges under certain hydraulic 

 conditions. 



Experiments at Bonneville exploring the 

 preference of adult migratuig salmonids for light 

 conditions have demonstrated that pronounced 

 species differences prevail. Sleelhead presented 

 with a choice of entering a light or dark channel 

 exhibited a marked preference (80 percent) for 

 the dark channel. In contrast, chinook salmon 

 entered the light and dark flumes in nearly equal 

 proportions, indicating no particular preference 

 for either condition. In both instances, fish were 

 light adapted prior to exposure to the test 

 condition. 



Figure 1 7. — Swimming performances of cfiinook sal- 

 mon and steeltiead trout by size in wafer velocities 

 of approximately 13 and 16 feet per second. 



for transport. It might also be expected that fish 

 would have to expend more energy in passing 

 through the higher velocities. Ma.ximum swim- 

 ming speeds in relation to the water were 26.7 

 f.p.s. for steelhead trout and 22.1 f.p.s. for chinook 

 salmon measured over a distance of 30 feet. 



ATTRACTION OF FISH 



FISHWAY HYDRAULICS 



The importance of controlling hydraulic condi- 

 tions in fishway pools and channels has been 

 brought to light in several experiments at the 

 Bonneville laboratory. A change in fishway flow 

 from a plunging to a streaming condition was 

 found to halt temporarily almost all movement 

 for a period of several minutes. Such information 

 indicated that unstable flow conditions could 

 seriously interfere with fish movement in fishways. 



Chinook and silver salmon and steelhead trout 

 presented with a choice between entering channels 

 carrying either a "high" or a "low" water velocity 

 demonstrated a significant preference for tlie 

 high-velocity channel in virtually every test. The 

 response to the high velocity is given in table 3. 



Following these tests an additional experiment 

 was conducted in which a sample of chinook 

 salmon and steelhead trout were presented with a 

 choice between flows of approximately 3 and 13 

 f.p.s. The high-velocity chaimel was chosen by 

 89.5 percent of the chinook and by 75.6 percent 

 of the steelhead. The choice of the high-velocity 

 channels by the chinook salmon is of particular 

 interest since approximately half of the total 

 sample of 51 fish failed to negotiate the channel 

 after entry. Fish swept back after failing to pass 

 the flume again selected the higher velocity on 

 their second attempt. 



Demonstration of the importance of maintaining 

 a uniform flow in fishway channels was evidenced 

 in a series of tests in which fish were passed through 

 an open channel approximately 2 feet deep. 



•5 6 

 o 



o c 3 



— o 

 o u 

 a> V 



- " 4 



E Z 



I I Steelheod Troul 

 Chinook Soimon 

 Silver Solmon 



i 



Woler velocity 



8 134 



in feel per second 



Figure 18. — Salmonid rote of movement in an open 

 cf)annel with water velocities ranging from 2 to 1 6 

 feet per second. 



11 



