that 98 out of 101 fishermen stressed the necessity of maintenance of 

 uniform pool levels as far as possible. They thought that winter fluctu- 

 ations resulted in a decrease in fish populations and condition. 



Regarding the effects of winter drawdowns on fish in Pools 24, 25, 

 and 26, the Fisheries Technical Section of the Upper Mississippi River 

 Conservation Committee (UKRCC, 1951: 25) reported that: 



in 1945-1946 ... an estimated 15,811 pounds of dead 

 fish were observed in Pool 25 (Lincoln Co., Mo.) . . . rescue 

 crews obtained approximately 4,000 pounds of fish (from 

 Pool 25) . . . observers estimated 15% tons of fish were 

 removed by the public from sites in the area and about 

 11 tons were harvested commercially near Ellsberry, Mo. 

 During the 1949-50 non-navigation season, neither Pool 24 

 nor 26 were included in the intensive drawdown. The fluc- 

 tuation of the water level in these 2 pools was relatively 

 slight and no fish mortality was reported in either pool 

 . . . during the same period, fish kills were noted in 

 other pools which were drawn down. 



Winter drawdown has not been practiced by the St. Louis District 

 since 1970. Natural fluctuations in water levels stranded fish in back- 

 waters in pre-construction as well as post-construction times. 



Fish rescue operations were relatively expensive, and there was 

 never any sound evidence that they had a beneficial effect on fish 

 populations in the river. 



Fall and winter drawdowns are sometimes used as a fish management 

 tool in relatively deep reservoirs, as a result of favorable results ob- 

 tained in places like the Tennessee Valley. One purpose of reservoir 

 drawdown is to force young fish out of protected shallows into deeper 

 water, where they can be preyed upon by larger fish, thus preventing an 

 overpopulation of stunted fish which are undesirable for a sport fishery. 

 Overpopulation and stunting can occur in reservoirs, which are semi- 

 closed systems. Stunting and overpopulation were never problems in large 

 open systems like the Illinois and Mississippi Rivers, where exchanges 

 of fish between backwaters and the rivers could occur during times of 

 high water. The very shallow lakes and backwaters along the Mississippi 



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