112 



ing these conservative totals, the number of trout was comparable to the 

 number estimated for the two upstream sections, while weight was at least 

 24 and 54% greater than the biomass estimated for the two upstream sections. 



Fishery (1964-1976) 



Since Clark Canyon Reservoir began impounding water in 1964, the 

 Montana Department of Fish and Game has annually stocked rainbow trout. 

 Trout have been planted in varying numbers and sizes and at different 

 times of the year (Table 14). Creel census information during 1967, 

 1968, 1970 and 1973-76 showed over 90% of the catch to be rainbow trout, 

 of which 90-95% were of hatchery origin. Brown trout was the other trout 

 species taken. 

 Growth of Hatchery Rainbow Trout 



Characteristic of most newly created reservoirs, trout growth was 

 exceptional immediately following impoundment. One and one-half years 

 after introduction, the 3-5 inch fingerlings planted in October, 1964 

 averaged greater than 17.5 inches. After being in the reservoir 27 months, 

 these fish averaged 21.0 inches in length. Hatchery rainbow were marked 

 and their growth monitored by creel census from 1970 through 1975. Trout 

 growth was not as great during this period as in 1965 and 1966. Twelve 

 months following introduction, the trout planted in 1970, 1971 and 1972 

 averaged about 15.0 inches (Figure 6). After two years, these rainbow 

 trout averaged between 18.5 and 19.0 inches. Only a few known age trout 

 were creeled after three years and these averaged 21.0 inches. 



