7fi FISH HATCHERY MANAGEMENT 



improved enumeration technique, better food production, or control of 

 disease, predators, or competitors. 



Production of 3- to 6-inch bass fingerlings requires careful attention to 

 size uniformity of the fry stocked. The number of fry stocked is reduced by 

 75 to 90"(i below that used for 2-inch bass production. Growth past a size 

 of 2 inches must be achieved mainly on a diet of immature insects, mainly 

 midges. If a size larger than 4 inches is needed, it will be necessary to pro- 

 vide a forage fish for the bass. There are no standard procedures for this, 

 but one method is to stock 17-inch bass at a rate of 1,000 per acre into a 

 pond in which fathead minnows had been stocked at a rate of 2,000 per 

 acre 3 or 4 weeks previously. The latter pond should have been fertilized 

 earlier with organic fertilizer and superphosphate so that ample zooplank- 

 ton will have developed to support the minnows. The minnows are allowed 

 to grow and reproduce to provide feed for the bass when they are stocked. 

 If weekly seine checks show that the bass are depleting the supply of 

 forage fish, additional minnows must be added to the pond. Variable 

 growth among bass fingerlings is common but if some fingerlings become 

 too much larger than others, cannibalism can cause heavy losses. If this 

 occurs, the pond must be drained and the fingerlings graded. 



BLUEGILL 



Numerically, bluegills and redear sunfish are the most important of the cul- 

 tured warmwater fishes. Generally, spawning and rearing occurs in the 

 same pond, although some fish culturists transfer fry to rearing ponds for 

 one reason or another. 



In previously prepared ponds, broodstock bluegills 1 to 3 years old are 

 stocked at a rate of 30 to 40 pairs per acre. Spawning- rearing ponds for 

 bluegills can be stocked in the winter, spring, or early summer. About 60 

 days are required to produce harvestable-size fingerlings under average 

 conditions. 



CHANNEL CATFISH 



Channel catfish reared in ponds are stocked at a rate of 100,000 to 200,000 

 fry per acre. At these rates, survival should be 80%, and 3- to 4- inch finger- 

 lings can be produced in 80 to 120 days if there is adequate supplemental 

 feeding. Stocking at a higher rate reduces the growth rate of fingerlings. A 

 stocking rate of 40,000 to 50,000 per acre yields 4- to 6- inch fingerlings in 

 80-120 days if growth is optimum. 



Although channel catfish can be reared on natural food, production is 

 low compared to that obtained with supplemental feeding. A well- fertilized 

 pond should produce 300-400 pounds of fingerling fish per acre, with no 



