No young-of-year walleye were collected in the Yellowstone 

 River or its tributaries. This suggests that virtually all walleye 

 larvae produced in the Yellowstone River system drift downstream 

 into the Missouri River (Garrison Reservoir) . Priegel (1970) 

 documented that walleye fry drifted downstream in tributary 

 streams, probably 150 or more km, to reach Lake Winnebago. The 

 spawning area 163 km upstream from the mouth of the Yellowstone is 

 the uppermost walleye spawning ground found (Table 18) . 



Age, Growth, and Population Statistics During Spring 



The mean length and weight for the walleye spawning population 

 at Intake in spring 1978 was 414 mm and 656 g for males and 517 mm 

 and 1354 g for females. The youngest mature males collected were 

 age 2 but were not abundant in the population until age 5 (Table 

 19) . Females did not appear in the population until age 5. Age 6 

 walleye comprised over 40% of the population of both males and 

 females. The mean length of age 3 walleye was 358 mm and length 

 increased an average of 30 mm for each successive year in age 

 (Table 20) . 



Table 19. Age structure of the spawning walleye population 

 downstream from Intake diversion, spring, 1978°. 



Age 2 3456789 10 



Males 



% of Total 7 17 23 44 5 3 1 



Females 



% of Total 14 41 23 14 9 



Based on scales examined from 835 fish. 



81 



