SOME IMPORTANT BAIT FISHES 



minnow ranges in length from 1^/2 

 to 4 inches, the male being con- 

 sistently larger than the female. 

 The life span of the hatchery- 

 reared fathead minnow is from 12 

 to 15 months, depending on the size 

 of the fish at maturity. It is quite 

 certain that during the early 

 spawning season a large majority 

 of the males die within 30 days after 

 the onset of spawning activities, 

 and that a large percentage of the 

 gravid females die within 60 days. 

 Immature fatheads, ranging in 

 length from 1 to 2 inches, even 

 though a year old will die shortly 

 after they become gravid at the 

 age of about 15 months. It has 

 been noted that a small percentage 

 of the adult hatchery-reared fat- 

 heads are sterile, and also, that 

 these fish live longer and grow 

 larger than the fertile fish. 



In Missouri, the fathead is com- 

 mercially produced by two types of 

 culture: intensive and extensive. 

 Intensive culture refers to the op- 

 eration of hatcheries where large 

 populations of fish are fed artifi- 

 cially. Extensive culture refers to 

 hatchery operations where smaller 

 fish populations are fed natural 

 foods produced by fertilization. 

 Both methods have merit, depend- 

 ing on the type of water available 

 at the hatchery site. Intensive fat- 

 head culture requires much more 

 labor and initial capital expendi- 

 ture than does extensive; however, 

 fish may often be produced in 

 greater numbers and at lower cost 

 by the intensive type of fish farm- 

 ing. 



Intensive culture of fatheads 



To practice intensive fish culture, 

 it is necessary to have a source of 

 flowing, cool water from a spring or 

 well. The ponds should not be 

 larger than 1 acre or smaller than 

 1/4 acre. The depth of water should 

 range from 2 feet at the shallow end 

 to 6 feet at the drain, and average 

 about 3 feet deep. The pond 

 should be equipped with a control- 

 lable inlet and similar bottom 

 drain. To raise fatheads profit- 

 ably, it is necessary to have at least 

 6 ponds available for propagation, 

 and it is much more economical, as 

 far as production costs are con- 

 cerned, to have 12 to 15 ponds. In 

 every unit of 6 ponds, it is desirable 

 to use only 2 for reproductive pur- 

 poses, leaving the remaining 4 for 

 growing ponds. The ponds to be 

 used for reproductive purposes 

 should be ballasted along two banks 

 with rocks ranging in size from 6 

 to 12 inches in diameter, or with 

 tile (fig. 40). This construction 

 should extend from about 6 inches 

 above the planned normal water 

 level to a depth where the rocks 

 will be covered by about 2 feet of 

 water. The purpose of this instal- 

 lation is to provide adequate 

 spawning facilities for the fat- 

 heads; at the same time, it offers 

 considerable protection to the levees 

 against pond erosion. 



The brood ponds should be 

 stocked in the early part of April, 

 and the breeders should consist of 

 both mature and immature fat- 

 heads in ratio of about 00 percent 



80 



