rate of growth and the reduction of the number of 

 bass has resulted from competition and predation 

 by the crappies, as well as from fishing. Hook-and- 

 line fishing has apparently removed a larger percent- 

 age of the bass than of the crappies. In June, 1934, 

 a group of wardens under the direction of Chief In- 

 spector Erio contacted 2,097 fishermen and enumera- 

 ated their catch during the first three days of the 

 first open season. Their catch included 2,544 bass, 

 but only 74 crappies. This is because bass seem to 

 bite better than crappies in summer. The growing 

 scarcity of bass in this lake does not seem to be due 

 to their failure to spawn or to lack of spawning 

 places. 



The best way to reestablish the bass in satisfactory 

 numbers would seem to be (1) to relieve them from 

 competition and predation by taking out more crap- 

 pies and (2) to plant bass too large to be swallowed 

 by crappies. 



Crappies 



Crappies made up 46 percent of all the larger fish 

 taken in the four surveys. The facts about their 

 growth and numbers are shown in the accompanying 

 diagrams. Of the very large carnivorous fishes, the 

 white crappie is most numerous. It may be noted 

 that the decline in abundance of bass has taken place 

 at the same time as a corresponding increase in the 

 number of white crappies. 



Within the past few years, larger crappies of both 

 species have been caught or handled in Horseshoe 

 Lake than in other Illinois waters in recent decades. 

 A few of the very largest of these have been identi- 

 fied as hybrids between the two species. The larg- 

 est hybrid was 17.1 inches long and weighed 4.3 

 pounds. It was caught in March, 1936. 



Fishermen have noticed that large specimens of 

 most kinds of fish are usually females. For example, 

 23 out of 27 of these large white crappies were fe- 



Below. — In the spring of 1932 the breeder bass previously 

 placed in the lake spawned successfully. In the absence of 

 many predators a large part of this brood survived. At the 

 same time a large brood of crappies was also produced and 

 survived. In succeeding years the bass spawned, but nearly 

 all of the young have disappeared — probably eaten by the 

 crappies. In each year since 1934, the number of legal-sized 

 bass has been reduced to one-half or two-thirds of the 

 number present the preceding year. The original 1932 brood 

 still makes up over 90 percent of the bass population as 

 shown by the 1936, 1937 and 1938 surveys. 



Largemouth Black Bass 



1934 



NO 



1935 



^ 



^M 



RELATIVE NUMBERS OF DIFFERENT SIZES OF 



WHITE CRAPPIES 



12 14 



IN Inches 



The white crappie, in contrast to the largemouth bass and 

 the black crappie, produced a rather small brood in 1932 

 when the lake was new. Unlike these other species, it has 

 produced moderate-sized broods each year which have es- 

 caped destruction. This has resulted in a progressive increase 

 in their numbers which is shown in the diagram below. 



White Crappie 



< 



O 5- 



1937 



I93S 



. ZZZZZZZZ 



1934 



NO 



Survey 

 1935 



1936 



1937 



1936 



—5- 



