Young sauger appear to move upstream beginning at age 0+ and 

 continue during their second year of life. Tag returns and age 

 structure from electrof ishing samples revealed that although this 

 upstream migration began the first year for some sauger, for most 

 one or more years passed before substantial upstream movement 

 occurred. Large concentrations of juvenile sauger were noted from 

 Glendive (river km 145) downstream. 



Flows in Tongue River during the time of sauger migration and 

 spawning ranged from 370 to 720 cfs during 1976-1979 and were 

 generally above 440. Numbers of sauger entering the Tongue River 

 each of these four years was very similar. Flows during 1980 were 

 much lower, ranging from 94 to 404 cfs during the spawning run. 

 Numbers of sauger entering the Tongue River in 1980 were 

 significantly smaller than each of the previous four years. 

 Maximum numbers of larval sauger drifting in the Tongue River in 

 1980 was estimated to be one third of that the previous year. A 

 critical low flow, 300 cfs appeared to cause sauger emigration 

 during the middle of the spawning period. This critical flow is 4 

 times the instantaneous discharge allocated for instream purposes, 

 75 cfs. This flow is much too low to maintain the Tongue River as 

 an important sauger spawning area. 



Optimum flows were predicted for the Intake spawning area 

 (primarily walleye) using observed depth, velocity, and substrate 

 criteria at egg sampling sites. Predicted acceptable spawning 

 flows ranged from 6000 to 11,000 cfs. In 1977 and 1978 discharge 

 during time of spawning was usually within this range. Numbers of 



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