not established from the few chinook seilmon 

 that were trapped in 1956. Fyke nets, oper- 

 ated at the dam commencing April 2, 1956, 

 caught young chinook. Thus apparently there 

 is an early downstream movement of this 

 species . 



Following the high water season the 

 trap was operated on a 24-hour-a-day sched- 

 ule and counts represented the daily passage 

 of fish through the bypass. Figure 14 

 illustrates the seasonal migration of chi- 

 nook salmon during summer and fall months. 

 Substantial migrations occurred during this 

 part of the year with peaks in late August, 

 mid-September, and mid-October. 



Steelhead trout . — Young steelhead were 

 taken in all months that the trap was oper- 

 ated although in less abundance thjui chinook. 

 Daily evening counts during the spring sea- 

 son, shown in figure 15, indicate the peak 

 may have been at the time trapping was ini- 

 tiated. There was no way of knowing the 

 extent of migration during the high water 

 season which followed the apparent upward 

 trend of abundamce of steelhead in May. 



The peak of abundance occurred in 

 August and September during the summer suid 



fall months, figure 16. Whereas chinook 

 salmon reached a peak in October, steelhead 

 declined in abundance this month. 



Fish Movements and Water Flow 



Figure 17 gives the discharge in 1955 

 and 1956 for the Wenatchee River at Plain, 

 Washington, located approximately 20 miles 

 above Tumwater Dam. In comparing blueback 

 catches and water flow, it is observed that 

 possibly the bulk of the blueback migration 



20 22 24 26 28 30 2 



APRIL 



8 10 12 14 16 18 20 

 MAY 



Figure 15 . — Spring 1955 downstream migra- 

 tion - steelhead trout^ Tumwater Dam. 

 Counts from 7 p^m- to 12 midnight. 



w 



11 



r^r' 



"^ -1- 



1 



5 10 15 20 25 30 5 10 15 20 25 30 5 10 15 20 25 30 5 10 15 20 25 30 5 10 15 20 



JULY AUGUST SETEMBER OCTOBER NOVEMBER 



Figure l6. — Summer and fall 1955 downstream migration - steelhead trout^ Tumwater Dam. 

 Counts from 2h- hour days. 



12 



