102 FISH HATCHERY MANAGEMENT 



experience. If the species to be reared is a predator species such as large- 

 mouth bass, striped bass, or walleye, a typical program might be as follows. 



In spring, while the pond is still dry, disk the pond bottom. Apply lime 

 if needed to bring pH into a favorable range. The fertilizer can be spread 

 on the dry pond bottom and the pond then filled, or the pond filled and 

 then the fertilizer spread; the following example assumes it is on the pond 

 bottom. 



Spread: 500 pounds per acre chopped alfalfa hay; 200 pounds per acre 

 meat scraps; 200 pounds per acre ground dehydrated alfalfa hay; 50 

 pounds per acre superphosphate; 10 pounds per acre potash; 1,000 pounds 

 per acre chicken manure. Fill the pond and wait 3 to 5 days before stock- 

 ing fish. 



This fertilizer program for sandy loam soils and slightly acid waters will 

 produce an abundance of zooplankton needed for rearing the predator 

 species. Usually this amount is added only one time and will sustain the 

 pond for 30-40 days. If the fish crop is not of harvest size by that time, a 

 second application of all or part of the components may be needed. 



If the species to be reared is a forage species such as bluegill, redear sun- 

 fish, goldfish, or tilapia, the following program might be used: 100 pounds 

 per acre ammonium nitrate; 200 pounds per acre superphosphate; 50 

 pounds per acre potash; 100 pounds per acre chopped alfalfa hay; 300 

 pounds per acre chicken manure. This fertilizer program will produce more 

 phytoplankton than the one outlined for predators. As with the one above, 

 this program will have to be repeated about every 30-45 days. 



The type of fertilizer program that works best at any particular station 

 will have to be developed at that station. The program that works best at 

 one station will not necessarily work well at another. The examples given 

 above are strictly guidelines. 



AQUATIC VEGETATION CONTROL 



Aquatic plants must have sunlight, food, and carbon dioxide in order to 

 thrive. Elimination of any one of these requirements inhibits growth and 

 eventually brings about the death of the plant. The majority of the com- 

 mon water weeds start growth on the bottom. Providing adequate depth to 

 ponds and thus excluding sunlight essential to plant growth may prevent 

 weeds from becoming established. Water plants are most easily controlled 

 in the early stages of development. Control methods applied when stems 

 and leaves are tender are more effective than those applied after the plant 

 has matured. In most cases, seeds or other reproductive bodies are absent 

 in early development and control at this time minimizes the possibility of 

 reestablishment. 



The first step in controlling aquatic vegetation is to identify the plant. 

 After the problem weed has been identified, a method of control can be 



