from Sidney (river km 56) because of reduced velocities and 

 unsuitable substrate in this section of river. Water temperature 

 during peak spawning was usually 12°C or greater. 



After spawning the majority of walleye return downstream to 

 Garrison Reservoir while most sauger remain near the mouth of the 

 two tributaries or migrate upstream. Intake diversion (river km 

 114) does not appear to severely impede upstream movement of sauger 

 while Forsyth diversion (river km 381) may hinder fish passage. 



Sauger and walleye larvae hatch during the end of April or 

 beginning of May when water levels are beginning to increase from 

 mountain runoff. The distribution of larvae and young-of-year 

 sauger indicate that virtually all sauger hatched in the Tongue and 

 Powder rivers drift to downstream areas near the mouth of the 

 Yellowstone River (distances up to 300 river km) . No young of year 

 walleye were collected in the Yellowstone River suggesting that 

 virtually all walleye drift into Garrison Reservoir. 



Sauger move upstream during the first year of life. By autumn 

 a few young of year were captured as far upstream as Miles City 

 (river km 298) and Forsyth (river km 381) . 



Estimates of the sauger population at Miles City during the 

 fall of 1978, 1979, and 1980 were 248, 177, and 226 per kilometer, 

 respectively. Low numbers in 1979 may have been the result of 

 severe ice conditions during the previous winter. 



INTRODUCTION 



The Yellowstone River and two of it's major tributaries, the 

 Tongue and Powder rivers, pass through lands undergoing or slated 



