SOME IMPORTANT BAIT FISHES 



resort to a mechanical pump. 

 About the only advantage of this 

 type of hatchery construction is its 

 relatively low initial cost and the 

 ease with which the site can be ob- 

 tained. The disadvantages are that 

 during the warm summer months 

 the operator must supply the ponds 

 with cold water from a deep well or 

 provide a holding station where 

 cold water is available to store his 

 salable minnows. 



In the actual operation of an ex- 

 tensive type of minnow hatchery 

 for fathead production, it is not 

 necessary nor is it desirable to bal- 

 last the banks of the pond with 

 rocks for the breeding fish. Usually 

 the large reservoir pond is used for 

 this purpose, and the water level 

 may fluctuate as much as 10 feet 

 during a season. Also, these large 

 ponds usually contain enough rocks, 

 roots, and other debris to provide 

 sufficient spawning structures for 

 the number of breeders introduced. 

 In stocking a pond with breeders, 

 about 4,000 fish per acre are used, 

 consisting of about 60 percent 

 adults and 40 percent juveniles. 



When the water temperatures in 

 the reservoir pond reach 65° F. 

 spawning occurs, and within a 

 week or 10 days fry appear on 

 the surface. Within 8 to 4 weeks, 

 the fry should be sufficiently large 

 and abundant enough to warrant 

 transfer, by trap net or bobbinet 

 seine, to the smaller growing 

 ponds. Since there is no assur- 

 ance of an incoming supply of 

 fresh water, the artificial feeding 

 of both the breeders and the fish 



in the growing pond has to be 

 quite restricted. The same rule 

 applies to fertilizing the ponds. 

 During the midsummer period in 

 Missouri, the water temperatures 

 of reservoir-type ponds usually are 

 too high for continued fathead re- 

 production. At this season, it is 

 desirable to fertilize both the 

 brood ponds and the growing 

 ponds with a combination of su- 

 perphosphate and cottonseed meal 

 ill equal proportions at the rate 

 of 25 pounds an acre every 10 

 days, or until a plankton turbidity 

 colors the water sufficiently that a 

 white object cannot be distin- 

 guished at 114 feet. If the pond 

 becomes too rich in organic mat- 

 ter, it is quite possible that all of 

 the fatheads will die from oxygen 

 depletion. At best, it is more 

 practical to fertilize sparingly, and 

 allow the natural fertility of the 

 soil to determine the productivity 

 of the pond. 



Harvesting and storing the fish 



If some of the fathead minnows 

 attain a salable size during the 

 summer months, they can be re- 

 moved by trapping or seining. In 

 the fall or at any time during the 

 cooler seasons of the yeai-, the pond 

 can be drained and the entire pop- 

 ulation removed. These fish in 

 turn can be graded as to size and 

 stored for future sales, or they can 

 be placed in different ponds for 

 additional growth. The drained 

 ponds can again catch the surface 

 runoff, thus storing the next year's 

 water supply. 



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