NOV. DEC. JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC. JAN.FEB.MAR. APR.MAY JUN. JUL. 

 1964 



1963 



1965 



Figure 4. — Estimated emigration from Brownlee Reservoir of juvenile native spring chinook salmon from 

 Eagle Creek and Weiser River, November 1963 to July 1965. 



Table 7. — Estimated immigration of juvenile native fall 

 chinook salmon into Brownlee Reservoir from the Snake 

 River and estimated emigration from the Reservoir, May 1, 

 1963 to August 1964 (all fish of 1963 year class) 



> Includes 2,700 fish captured at the Idaho Power Company barrier net. 



to leave the reservoir as age-group fish in 

 November 1963, and the emigration continued 

 through June 1964 (fig. 4). Distinction between 

 fish from the Weiser River and those from 

 Eagle Creek was not always possible, but knowledge 

 of the age of fish at the time of downstream 

 migration to the reservoir provided a basis for 

 their identification at certain times of the year. 

 Krcma and Raleigh (1970) have shown that fish 

 from the Weiser River do not enter the reservoir 

 until spring 1 year after hatching, whereas fish 

 from Eagle Creek enter at age in the fall and 

 again as age-group I in the spring. Spring 

 chinook salmon that left the reservoir in the fall. 



winter, and early spring, therefore, were probably 

 from Eagle Creek; fish leaving later in the spring 

 and in early summer could be from either the 

 Weiser River or Eagle Creek. 



The emigration of the 1964 year class of spring 

 chinook salmon was estimated at 14,000 fish, 

 51 percent of estimated immigration. Most of these 

 fish were from Eagle Creek. Additional catches of 

 juvenile migrants from Eagle Creek were made in 

 the stream, transported downstream below Oxbow 

 Dam, and released (Krcma and Raleigh, 1970). 

 Juvenile spring chinook salmon that entered the 

 reservoir in late March and early April 1964 

 migrated rapidly through the impoundment. Peak 

 emigration was in mid-April, and the migration 

 ended in late July (fig. 4). 



Kokanee 



The origin of, or reasons for, some migrations of 

 juvenile kokanee into Brownlee Reservoir are not 

 completely understood, but most fish observed 

 during the present study were probably from the 

 Payette River system (Payette Lakes and Cascade 

 and Deadwood Reservoirs). Kokanee periodically 

 migrate however, and rather large numbers of 

 fingerlings entered Brownlee Reservoir in 1964 



Table 8. — Estimated immigration of juvenile native spring chinook salmon into Brownlee Reservoir from Eagle Creek and 

 the Weiser River and estimated emigration from the Reservoir, November 1, 1963 to August 1966 



JUVENILE SALMON AND TROUT EMIGRATION FROM BROWNLEE RESERVOIR 



251 



