LAKE MANAGEMENT REPORTS 



1. Horseshoe Lake near Cairo, Illinois 



David H. Thompson and 

 Illinois Natural H 



For many years the Illinois Natural History Sur- 

 vey has been measuring fish populations and fish 

 production. Among the various types of Illinois 

 waters studied, it has been found that each tends 

 to have the capacity to support a certain number of 

 pounds of fish per acre which is constant from year 

 to year. This number of pounds per acre remains 

 constant even though there may be ten times as 

 many fish (of one-tenth the average weight per fish) 

 in some years as in others. When this amount of 

 fish flesh per acre is disturbed by putting in or 

 taking out fish or by floods or drouths, readjust- 

 ment takes place much more rapidly than is popu- 

 larly supposed. 



When a new lake is stocked with a few breeder 

 fish the saturation point is usually reached in about 

 a year. When one-fourth, or less, of the total 

 amount of fish in a lake is removed during the 

 course of a season, readjustment takes place so rapid- 

 ly that changes in abundance are not detectable. 

 This means that the yield of game fishes from an 

 acre of water can be many times the amount taken 

 out by ordinary fishing. 



Geokce W. Bennett 

 istory Survey 



Fish grow to more desirable sizes and furnish a 

 better quality of food and sport when their numbers 

 are reduced enough to give rapid growth rates. Good 

 farmers understand this view of livestock and crop 

 production and practice it continually. The follow- 

 ing is an account of the changes which have taken 

 place in Horseshoe Lake since its reconstruction in 

 1931. 



Description 



Horseshoe Lake embraces about 2.400 acres of 

 water with a 1,400-acre island in the center. The 

 Illinois Department of Conservation owns the island 

 and about two-thirds of the water surface and main- 

 tains it as a waterfowl refuge. The lake is located 

 about 12 miles northwest of Cairo on Highway 150. 



Horseshoe Lake is part of a former channel of the 

 Mississippi which has grown up in cypress. Cypress, 

 gum, willow and buck brush grow throughout all 

 parts of the lake, although the trees are more scat- 

 tering along the east side, leaving considerable areas 

 of open water. With the exception of some flooded 

 pasture lands, the remainder of the lake is grown up 

 in timber and brush. The east side of the lake has 

 a uniform depth of about six feet; the remainder is 



KINDS, SIZES AND NUMBERS OF FISH IN HORSESHOE LAKE 



Kind 



Largemouth Bass . 

 White Crappie ... 

 Black Crappie . . . 



White Bass 



Yellow Bass 



Warmouth Bass . . 



Bluegill 



Green Sunfish .... 

 Flier Sunfish 



Grass Pike . . 

 Spotted Gar . 

 Dogfish 



Channel Cat 



Black Bullhead . . 

 Yellow Bullhead . 



Gizzard Shad . . 

 Golden Shiner . 



Carp 



Rcdmouth Buffalo. . . 

 Mongrel Buffalo. . . . 

 Smnllinouth Buffalo . 



Quillback 



Redhorsc 



Spotted Sucker 



Chub Sucker 



Total 



Total No. 

 Handled 

 1934-38 



Average Total Length in Inches 



235 



1,044 



3.913 



3 



IS 



9 



969 



2 



825 



14 



2 



17 



9 



1,122 



329 



1,244 

 11 



217 



618 



33 



12 



9 



1 



139 



1 



10,793 



1934 



12.4 



10.3 



6.3 



7.3 

 5.3 



9.1 

 10.8 



9.1 



19.8 

 13.8 

 15.2 



12.9 



1936 



16.2 



10.7 



7.9 



6.9 



6.0 



10.0 

 10.9 



9.7 



20.8 

 17.0 

 20.3 



16.2 



1937 



15.4 



10.9 



7.6 



6.8 



5.8 



10.5 

 12.1 



10.4 



21.5 

 17.9 

 22.7 



16.8 



1938 



Estimated Number in Lake 

 during the Past Year 



16.2 

 8.5 

 7.9 



6.8 



5.9 



11.1 

 11.4 



10.7 



22.6 

 18.1 

 21.7 



17.7 



5,000 to 10,000 

 250,000 to 350,000 

 500,000 to 700,000 



150,000 to 250,000 

 4,000 to 15,000 



150,000 to 250,000 

 35,000 to 50,000 



50,000 to 200,000 



25,000 to 50,000 



25,000 to 100,000 



1,000 to 5,000 



5,000 to 20,000 



1,200,000 to 2,000,000 



—2— 



