102 



weekend was sampled at least once per 4-week period. The weekdays were 

 thus sampled 8 days out of 20 per period. Every other weekend day was 

 sampled. The first weekend day per sampling period was selected at 

 random, then ewery other weekend day was sampled. Holidays were treated 

 as weekend days. Each selected sample day was divided into four 4-hour 

 periods. On each sample day, two counts were made, one in one 4-hour 

 period and one in a different period. The 4-hour periods were selected 

 at random while the hours within periods were in sequential order after 

 the first random selection. 



Catch was determined by contacting fishermen and recording number, 

 species and size of fish in the creel, plus the number of hours required 

 to take the fish. 



RESULTS 

 Reservoir Fish Populations 



Gill and trap nets were used to census fish populations in Clark Canyon 

 Reservoir from 1964 through 1972. Catch statistics for each year are given 

 in Tables 2 through 10. White sucker ( Catostomus commersoni ) was the domi- 

 nant species in the catch in all years. Other species captured were long- 

 nose sucker ( Catostomus catostomus ), burbot ( Lota lota ), mountain whitefish 

 ( Prosopium williamsoni ), brown trout (Salmo trutta), rainbow trout ( Salmo 

 gairdneri ), brook trout ( Salvelinus fontinalis ), and carp ( Cyprinus carpio ). 



White and Longnose Suckers 



Average lengths of white and longnose suckers at capture are compared 

 in Figure 4. The average length of both species remained fairly constant 

 between 1964 and 1968. Between 1968 and 1969, both species attained the 

 greatest annual increase in average length during the study period. After 



