Overfishing in a Small 

 Artificial Lake 



Onized Lake Near Alton, Illinois 



GEORGE W. BENNETT 



BEFORE North America was exten- 

 sively settled, native fish were the 

 staple food for a wide variety of 

 predatory mammals, birds and reptiles, as 

 well as for adult game and other piscivo- 

 rous fishes. With few exceptions, the nat- 

 ural predators captured small individuals 

 of the various fish species in proportion 

 to the relative abundance of such fish ; 

 as the larger individuals were less subject 

 to attack than the smaller individuals, 

 an accumulation of large fish resulted. 



Under conditions involving extensive 

 juvenile mortality, the survival of any 

 species of fish depends upon a high repro- 

 ductive potential, adjusted to compensate 

 for large losses. Most species that exist 

 today have a high reproductive potential. 

 The species that produce comparatively 

 few eggs have unusual behavior patterns 

 that offer special protection to their spawn. 



As the human communities have spread 

 to cover the continent, native fishes have 

 been subjected to a different kind of 



«A 



Onized Lake as seen when looking east from the spillway toward the lower end of the 

 larger bay. The fairly steep banks surrounding the lake are well grassed except where worn by 

 traffic. On the hill above the fishing pier, left, are brick grills, picnic tables and a shelter. 



[373] 



