-25- 



turbid ponds = Complete population estimates were not made for any bluegill 

 pond within the intermediate range, but 83 ppm was the most turbid water from 

 which large niimbers of small bluegills were recovered by seining, and weights 

 and numbers decreased markedly in more turbid ponds - 



Plankton Production 



In a correlated study (Claffey, 1955), 20 of the Payne County ponds were ./ 

 sampled once each month for 6 months of the 1954 growing season (April to 

 October) to determine the abundance of microscopic fish food. Volume of net 

 plankton in the surface waters (0 to 2 feet) in clear ponds (averages 0.0192 

 milliliters per liter) was 8 times greater than in ponds having intermediate 

 turbidities (average; 0=0024 milliliters per liter), and 12.8 times greater 

 th an in muddy ponds (averages 0.0015 m.illiliters per liter) (See Figure 3). 

 Less intensive investigations in 1955 showed small average differences due 

 to larger concentrations of plankton (chiefly zooplankton) in the surface 

 waters of a few turbid ponds = 



Light penetration appears to be the principal limiting factor in pro- 

 ductivity of turbid waters. Using a spectrophotometer, Claffey (1955) found 

 that in water having a turbidity of 25 ppm, only 24.9 percent of the original 

 light of the red wave lengths (the most penetrating) was visible at a depth 

 of 4 inches j° at 50 ppn, only 5 = 3 percent., At turbidities of 150 ppm , no light 

 of any visibly wave length penetrated through a depth of 3 inches. 



HATCHERY POND EXPERIMENTS 



The use of hatchery ponds was desirable because; 1) the farm ponds 

 exhibited individual variations in productivity due to differences in fertility 

 and physiography of the basins and watersheds which could not be fully evaluated; 



