Sauger upstream from Forsyth dam (section 4) were consistently 

 larger than the same age fish downstream (Table 7) . Grand mean 

 lengths of sauger collected in section 4 were significantly larger 

 than grand means for all three other sections all three years. The 

 sample in section 4 was composed mostly of older fish with only a 

 few yearlings collected and no young-of-year (Table 8) . 



The fact that the sauger population was much older and of 

 larger mean length in section 4 than all other areas downstream 

 (Table 7 and 8) may have been due to size selective passage over 

 Forsyth diversion. Small fish may have a more difficult time 

 negotiating this structure than larger sauger. 



Catch Rates and Relative Abundance During Autiuan 



Fifteen sample stations on the Yellowstone River were 

 electrof ished from Huntley to the North Dakota border during 

 autumn, 1977 to 1979. These approximately 8 km long stations were 

 lumped into 4 river sections (Figure 3) and analyzed accordingly. 

 Three to 8 times more sauger were captured in the 3 sections 

 downstream from Forsyth diversion (sections 1 through 3) than in 

 section 4, upstream from Forsyth diversion, during the 3 years of 

 sampling (Table 9) . This may be due to Forsyth diversion acting as 

 a partial barrier to sauger migrating upstream. The number of 

 sauger collected per 8 river km were very similar in the middle 2 

 sections (sections 2 and 3) each year. The number of sauger 

 collected in the downstream most section (section 1) was slightly 

 lower than that in sections 2 and 3 in 1978 and 1979 but slightly 

 greatly in 1977. 



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