104 Reproduction, Competition, and Predation 



to produce satisfactory angling over a longer period of time; others, to 

 favor one species; others, to give equal status to two or more species. 

 These variations in objectives can be accommodated only by diflFerences 

 in stocking methods. 



Fishes Used 



As early as 1944, evidence was available to show conclusively that 

 warm-water fishes raised in hatcheries were valuable only for stocking 

 new or renovated waters, or for stocking "waters seriously depleted as a 

 result of overfishing, pollution, or other special circumstances." ^^ 



The Bass-Bluegill Combination. The bass-bluegill combination was re- 

 born in the 1930's, although it had been used in ponds by Dyche before 

 1914 and by Barney and Canfield before 1922.*^' -^ In theory this com- 

 bination seemed excellent: both largemouth bass and bluegills would be 

 available for sport fishing; the bluegills would convert small invertebrate 

 animals in the pond into bluegill flesh and the small bluegills would serve 

 as food for the bass, the latter controlling excessive numbers of bluegills, 

 so that the few that survived would grow to large average sizes. 



As with most theories involving specific behavior patterns for animals, 

 the bass-bluegill combination did not always follow the original theory. 

 The bass often were unable to control the expansion of bluegill numbers, 

 and as Dyche -^ observed, the number of bass were more often controlled 

 by bluegills than vice versa. 



Shortly, however, biologists discovered that this combination furnished 

 satisfactory fishing for both bass and bluegills as long as neither species 

 was allowed to become overabundant. Interest was immediately directed 

 toward stocking specific ratios of these fish because these ratios had an 

 influence upon the length of time required for a newly-stocked pond to 

 reach overabundance, either of bluegills or bass. 



In the southeast, the bluegill was more easily controlled by bass than 

 elsewhere, and both species reproduced when one year old.'^- Thus, stock- 

 ing ratios were 1 to 15 in favor of bluegills. According to Swingle and 

 Smith,"^^ fertilized ponds should be stocked with 100 bass fingerlings and 

 1500 bluegill fingerlings per acre, unfertilized ponds with 30 bass finger- 

 lings and 400 bluegill fingerlings per acre. These ratios apparently were 

 not considered satisfactory for the Southwest as Brown ^^ recommended 

 either 200 to 400 largemouth bass per acre alone or in conjunction with 

 about the same number of bluegills or other pond fish. 



In the north central states, the bass were usually unable to attain sexual 

 maturity at the age of one year, although Clark -- reported that they did 

 so in Kentucky. Bluegills were sexually mature the next season after 

 hatching. Thus, when fingerling bass and fingerling bluegills were stocked 

 together in the same pond, the bluegills reproduced during the first 



