Figure 20. — Chinook salmon jumping over a weir. Salmon usually swim over an 

 overfall of tliis height. Proximity to the wall is characteristic. 



Table 5. — Comparison of passage times in "light" and "dork' 

 fishways ' 



' Six-pool flshway, l-on-16 slope, 4 feet wide, 6.3 feet deep and 

 between pools. 



-foot rise 



Tests involving around-the-clock passage of 

 salmonids have indicated that rate of ascent 

 during the night in a lighted fishway compared 

 favorably with ascent in daytime hours. A blue- 

 back salmon that ascended over a mile in height 

 during a 5}2-day period averaged 52 pools per 

 hour between 6:00 p.m. and 6:00 a.m. and 5.3 

 pools per hour from 6:00 a.m. to 6:00 p.m. Light- 

 ing in the fisluvay was coiislant throughout tlie 

 test period, ranging from 700 to 1,000 foot-candles 

 at the surface of the pools. Similar trends in day 

 and night movement were exhibited by steelliead 

 trout and chinook salmon when constant light 

 prevailed. 



13 



