62 



TABLE 23. Summary of turbidity (JTU) measurements for 10 sites on the 

 Beaverhead River. Samples were collected between March 13, 

 1975 and February 27, 1976. 



Cover plays an important role in limiting numbers of trout in the 

 upper river. The spring estimates of numbers of age II and older trout 

 in the Hildreth Extended (2) through Barretts Downstream (18) Sections 

 in both 1975 and 1976 (Figure 15) followed the same general trend as 

 willow bank cover (Table 1). Both decreased between the Hildreth (2) 

 Extended and Barretts Upstream Extended (15) Sections, then increased 

 substantially in the Barretts Downstream (18) Section. In the Wheat 

 (27) through Blaine (52) Sections, willow bank cover and numbers of 

 trout did not display similar trends, suggesting cover was not a major 

 factor influencing the decline in numbers of trout between these 

 sections. 



The low number of trout in the Grant (0.1) Section in Spring, 1976 

 (Figure 15) may partially reflect inferior cover. Compared to the 

 Hildreth Extended (2) Section, willow bank cover in the Grant (0.1) 

 Section was rated as poor. However, the low population of trout may 

 also reflect flow reductions and water quality. Average daily flows 



1 



. 



