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hatchery ponds, and in l arge reservoiti s. This was a two-year project, 

 initiated in January, 1954, and terminated December 31, 1955. The spring 

 and fall months were devoted primarily to the farm ponds the first year and 

 to both the farm and hatchery ponds the second year. Both summers were 

 largely devoted to the reservoir studies. 



A selected series of 39 farm pond s was rotenoned and restocked in the 

 spring of 1954. Turbidity and plankton samples were taken throughout the 

 tText two growing seasons. The fish populations were sampled at the end of 

 each growing season. These experiments provided information on growth, re- 

 production, and total production of fish, and on production of basic fish 

 foods in waters having a wide range of natural soil turbidities. 



The hatchery pond experiments were initiated in the spring of 1955. 

 This project involved artificially created turbidities in small, controlled 

 ponds from which the fish populations could be recovered by draining. Four- 

 teen ponds were used,* Six were kept turbid by the periodic addition of a 

 native clay and small amounts of sodium silicate solution (common Water 

 Glass), which served as a dispersing agent. A second six ponds were kept 

 turbid by adult carp, and four ponds were left untreated as controls, 

 although only the results from two proved usable. All ponds were stocked 

 with equal numbers of largemouth bass, bluegills and channel catfish. 



The studies of the two large r eservoi rs, one muddy, the other clear, 

 were made in order to measure some of the effects of turbidity on natural, 

 uncontrolled populations in larger bodies of water. Points of comparison 

 were fish growth and reproduction, relative abundance of important species. 



♦Originally 16 were used, but two control ponds were dropped because of 

 contamination by trash fishes and because of their small size. 



