Measurements obtained during August 

 for the two seasons indicate the 1955 mi- 

 grants to be larger than the 1956 group. 

 This was also indicated for the blueback. 

 (See figure 22, page 15). 



Fish Migration - Other Species 



Comparatively few species other than 

 salmon and steelhead were caught in the Tum- 

 water trap. The nzunes emd numbers of those 

 taken in 1955 are listed below: 



Fish Migration - Other Sampling Points 



Comparatively few fish were taken dur- 

 ing the intermittent trapping carried on in 

 Nason Creek and the Chiwawa River. In 

 general these catches agreed in timing and 

 age composition with catches at Tumwater 

 Dam. 



At Nason Creek both fry and finger ling 

 Chinook were taken in April and May and 

 only fry were captured in June and July. 

 Blueback fry were captured in April and no 

 blueback in its second year was taken. 



Catches of chinook in the Chiwawa River 

 consisted of both fry and fingerling size 

 groups during May. In July only the fry 

 were taken. 



SUMMARY AMD CONCLUSIONS 



Investigations of the fish runs in the 

 Wenatchee River system have revealed this 

 system to be an important salmon zuid steel- 

 head spawning and rearing area. Blueback 

 and chinook salmon and steelhead trout 

 migrate into the system and to the uppejr 

 areas in substantial numbers. Blueback 

 salmon have numbered over 50,000 adults, 

 chinook salmon over 5,000, and steelhead 

 trout in excess of 850 adults past Tumwater 

 Dam in recent years. 



The migration occurs from April to 

 November with an occasional few steelhead 

 migrating during winter months. The peak 

 of migration in numbers of salmon occurs 

 approximately the first week of August; 

 however, each species has its own peeik 

 period of migration. 



Spawning salmon are distributed through- 

 out the watershed on all favorable spawning 

 riffles. Spring chinook populate the tribu- 

 taries and upper reaches of the Wenatchee 

 River. Summer chinook spawn exclusively in 

 the main Wenatchee River. The bulk of these 

 are found from Leavenworth to the Columbia 

 although many migrate past Tumwater Dam. 

 Those summer chinook passing Tumwater Dam 

 spawn mostly within six miles of the dam. 

 Blueback salmon spawn mainly in the White 

 and Little Wenatchee Rivers with some spawn- 

 ers utilizing Nason Creek and the Wenatchee 

 River at the outlet of the lake. 



Young fish were observed to migrate 

 past Tumwater Dam for a minimum of eight 

 months of the year, from April to November. 

 The peak of the young blueback migration 

 occurs in April and May, prior to the normal 

 spring high water period. Chinook and 

 steelhead trout migrate in the spring and 

 throughout the summer and fall months. 



The age composition of the migrating 

 young fish indicates that the watershed above 

 Tumwater Dam provides a rearing area for the 

 young as well as spawning eireas for adults. 

 The majority of blueback migrate in their 

 second year. Chinook and steelhead trout 

 migrate in both their first and second years, 



17 



INT.DUP.,D.C.59- 57975 



