numbers of mature walleye and small numbers of mature sauger, was 

 discovered in 1976 just downstream from Intake diversion (river km 

 114) . In April of 1978, the number of mature walleye on the Intake 

 gravel bar was estimated to be 991 fish per kilometer. In 1980 

 numbers were thought to be ever higher. Of the 2488 mature walleye 

 and sauger collected form the Intake gravel bar from 1976 to 1980 

 24% were sauger, indicating that primarily walleye were using this 

 area for spawning. Migrant walleye are apparently becoming more 

 numerous in the Yellowstone River and are expanding their spawning 

 range. Intake was the only area where significant walleye 

 reproduction was documented in 1977 while 14 other spawning sites 

 were located in 1980 including 2 upstream near Glendive (river km 

 163) . Successful walleye reproduction in the Yellowstone River is 

 probably very important to walleye recruitment in the upper reaches 

 of Garrison Reservoir where suitable spawning areas may be limited 

 or lacking. 



Sauger and walleye eggs 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-the-year 

 sauger indicates that many sauger hatched in the Tongue and Powder 

 rivers drift to areas near the mouth of the Yellowstone River or 

 into the Missouri River. No young-of-the-year walleye were 

 collected in the Yellowstone River suggesting that walleye larvae 

 drift into Garrison Reservoir. 



102 



