males. This does not mean that the female grows 

 faster, but that the male dies off sooner. 



Bluegills and Other Sunfish 



The bluegill, more than any other species in the 

 lake, has maintained a uniform population and a 

 uniform size. It grows steadily and, apparently, re- 

 I^roduces successfully year after year. The bluegill 

 does not feed on other fishes extensively, probably 

 because of its small mouth, and is in the position 

 of a bystander in the struggle among the crappies 

 and the bass. 



The flier sunfish multiplied rapidly during the first 

 year and in 1934 constituted about onefifth of all 

 fishes taken. Since then it has declined and has al- 

 most disappeared. Only five were taken this year. 



A few other kinds of sunfishes and related species 

 have been taken in small numbers each year. None 

 of them shows any indication of reaching important 

 numbers, with the possible exception of the yellow 

 bass. 



Bullheads 



The black bullhead spawned very successfully in 

 1932. This brood reached an average length of 9 

 inches by 1934. Since that time they have been 

 growing one-half inch per year. There is no evidence 

 of the survival of any subsequent broods. In April, 

 1937, the black bullheads were all thin. They 

 seemed to be "all head and tail." Their flesh was 

 extremely soft and, on dressing, much of it pulled 

 off with the skin. During the present spring most 

 of them seemed to be in good condition although 

 a few were still poor. 



The yellow bullhead also produced a large brood 

 in 1932. Since then small broods have survived 

 about every second year. The yellow bulheads also 

 appeared to be starved in 1937, but not in 1938. A 

 few were examined post mortem in 1937 but no evi- 

 dence of disease or parasites was found. 



Bullheads are desirable food and it would seem a 

 good thing to make better use of those in Horseshoe 

 Lake. 



Forage Fish 



There appear to be about one -half million pounds 

 of game fish and bullheads in Horseshoe Lake which 



feed almost entirely on fish. Experiments have 

 shown that at moderate temperatures a largemouth 

 bass must eat about one percent of its weight in fish 

 per day in order merely to maintain its bodily proc- 

 esses, without any increase in weight. Since there 

 are about 200 days a year when the water of Horse- 

 shoe Lake is warm, this means that one million 

 pounds of forage fish are the minimal sustaining 

 requirements for these fish. Growth of these game 

 fish demands nourishment at the rate of 3 to 5 

 pounds of forage fish for each pound of new flesh 

 added. Thus, it is not improbable that as much as 

 two or three million pounds of small fish are con- 

 sumed annually. 



The principal items which compose this enormous 

 quantity of fish flesh are: 



(1) The young of larger fishes. 



(2) Both young and adults of a variety of min- 

 nows and other small fishes, of which the golden 

 shiner and the live -bearing top minnow have been 

 of outstanding importance. 



(3) The gizzard shad. 



The gizzard shad, while not useful for human con- 

 sumption, multiplies very rapidly and is an impwr- 

 tant food for game fish in lakes. It has a further 

 advantage in that it feeds upon the microscopic life 

 in the water and does not compete for food with edi- 

 ble species. From 1934 until 1937 the number of 

 adult gizzard shad declined steadily, probably be- 

 cause they were eaten by increasing numbers of crap- 

 pies of large sizes. Now that the large-sized crap- 

 pies are disappearing, the gizzard shad again shows 

 an increase. 



Rough Fish 



The carp and buffalo which make up the bulk of 

 rough fish in the lake now average about 5 pounds 

 each. Each female carp of this size produces one- 

 half million or more eggs. The young fish which 

 develop from these eggs are an important food item 

 of the game fish and tend to offset whatever com- 

 petition the carp and buffalo offer in other respects. 



NOTE: — Reprinted in part from Illinois Conserva- 

 tion, Summer. 1938. Cuts and type courtesy of 

 Illinois Department of Conservation. 



(63389) 



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