OPERATING THE HATCHERY 



be raised per acre of water by ar- 

 tificial feeding; consequently, only 

 lialf as many ponds are needed to 

 produce a good supply of min- 

 nows. Though the cost of produc- 

 tion is higher when the fish are 

 fed artificially, this may be offset 

 by a reduction in the original cost 

 of the pond and in the annual 

 maintenance. The artificial feed- 

 ing of heavy fish populations 

 (more than 2,000 pounds of fish 

 per water acre) requires a con- 

 stant flow of water through the 

 pond for aeration and cleanliness. 

 Only a small part of the natural 

 pond fertility and very little of 

 the fertility available from the 

 decomposition of food wastes are 

 used. Such concentrated popula- 

 tions must be treated for disease at 

 frequent intervals. (See page 50). 

 The Michigan Institute for Fish- 

 eries Research has developed a com- 

 bination method whereby creek 

 chubs are artificially fed and suck- 

 ers are raised on the bloom pro- 



duced by the decomposition of the 

 feeding wastes. The costs of pro- 

 duction were reduced under this 

 method. 



It should be remembered that 

 water temperatures have a direct 

 effect on the amount of food eaten 

 by fish. In cold-water ponds, the 

 consumption of food is low and 

 growth is slow. Also, when the 

 water becomes excessively hot, food 

 consumption declines and growth 

 becomes slow. 



HANDLING BAIT FISH 



While many species of fish can 

 be found in the tanks of the bait 

 dealers, certain species are more 

 popular and are handled in greater 

 quantities. These fish require dif- 

 ferent methods of propagation, but 

 the handling techniques will be 

 similar for all. The following 

 table lists the kinds of bait fishes 

 in greatest demand in the Lake 

 States : 



28 



