8 History of Fish Management 



cycle of size and numbers. In certain years there were ten times as many 

 fish as in other years, but the average weight was only one tenth as great. 

 This was a crappie-dominated cycle, wherein a dominant brood of 

 crappies curtailed the survival of its own young and those of other species 

 until this brood was decimated by natural mortality associated with senile 

 degeneration. Then another dominant brood was produced and the cycle 

 was repeated. The cycle shifted between high numbers of black crappies 

 with low numbers of white crappies and bluegills, and moderate numbers 

 of white crappies and bluegills with low numbers of black crappies. 

 Hence this investigation demonstrated that, in spite of constancy of 

 poundage, continual changes might be taking place among the fishes of 

 certain populations. 



One of the most significant studies, in that it helps to show the true 

 position of hatcheries in the fish management picture, was that of Car- 

 bine,^- who followed the spawning and hatching of nest-building cen- 

 trarchids in Deep Lake (Michigan). Fry were sucked through glass 

 tubing from nests guarded by males (to give identification of kind) and 

 counted. On the basis of these counts and the number of occupied nests 

 observed, Carbine estimated that the hatch of fish per acre in Deep Lake 

 exceeded one-half million during a single spawning season. Thus, he was 

 able to demonstrate that the hatching success of fishes in natural lakes 

 was as high or higher than that observed in fish hatcheries. 



POND MANAGEMENT 



Several investigators working with fish in ponds demonstrated the 

 capacity of fish populations to expand and contract in relation to tlie 

 capacity of the habitat to support them ^- and the relationships between 

 length of the food chains and poundages of fish supported.^^ 



Probably the most extensive pond research unit in North America was 

 developed between 1934 and 1944 by H. S. Swingle and E. V. Smith 

 at the Alabama Polytechnic Institute ( now known as Auburn University ) , 

 Auburn, Alabama. This unit consisted of more than 100 ponds which 

 could be drained and refilled; the ponds ranged in size from one tenth 

 of an acre to more than one acre. These ponds were used for developing 

 simple pond-management techniques which could be used by laymen for 

 increasing the fish yield of farm ponds. Recommendations that worked 

 well in the region of Auburn, Alabama, caught the interest of sports 

 writers throughout the country, and many magazines of national circula- 

 tion published articles on the Alabama methods of pond management. 

 The U.S. Soil Conservation Service, foremost pond-sponsoring agency in 

 the United States, and many State Conservation Departments, also put 

 to use the recommendations of the Alabama biologists. 



The national publicity on pond management stimulated such wide- 



