way T-test showed that the diameter of any one egg would be greater 

 than 1.90 mm 90 percent of the time. 



In 1978 and 1979 a total of 95 eggs were collected from four 

 ripe sauger collected in the Yellowstone and Tongue rivers. The 

 range of egg diameters was 1.60 mm to 2.00 mm with a mean of 1.78 

 mm and a standard deviation of 0.081. Only 4 (4%) of the eggs had 

 diameters larger than 1.90 mm. A one way T-test showed that any 

 one sauger egg would be 1.90 mm or smaller 93% of the time. Thus, 

 to separate eggs according to species, eggs with diameters from 

 1.60 - 1.90 mm were considered to be sauger and from 1.91 to 2.40 

 mm were identified as walleye. This closely follows observations 

 by Nelson (1968b) who noted that sauger and walleye egg diameters 

 ranged from 1.44 - 1.86 mm and 1.90 - 2.31 mm, respectively. 

 Diameters which had no overlap between species were less than 1.80 

 mm for sauger and greater than 2.00 mm for walleye, so eggs 

 collected within these ranges were considered positive sauger and 

 walleye eggs, respectively. 



During 1977, diameters of 162 eggs from the Intake gravel bar 

 were measured. Of these 4 were larger than 2.40 mm, did not have 

 the appearance of Stizostedion sp. eggs, and were not included in 

 the computations. Egg diameters ranged from 1.75 to 2.40 mm. Only 

 19 eggs (12%) were 1.90 mm or smaller indicating that a minority of 

 eggs originated from sauger (Table 5) . Only 6 eggs (4%) were 

 smaller than 1.80 mm (positive sauger). Of the 139 eggs considered 



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