FEEDING YOUNG BASS 



Stomach examinations of young bass carried on at the Hacketts- 

 town station show that during the first few weeks of their existence 

 their food consists almost entirely of microcrustacea, the predomi- 

 nating organisms in their order of importance being Cyclops, Simo- 

 cephalus, Chydorus and Scapholeberis. These forms can all be pro- 

 duced in the rearing ponds, and by the time the quantity of smaller 

 organisms has been reduced the fish will have attained a sufficient size 

 to take large organisms and will prefer them as food. It is at this 

 time that the supply should be supplemented by the daily introduction 

 of some form of natural food which is abundant and easy to secure. 



At this station we have fed the following organisms with good 

 results, all of which we can produce in quantities large enough to be 

 of importance : 



Abbott's minnow (Notropis chalyhaeus abbotti) 



Larva of the Mayfly (Callibaetis culex) 



Larva of the Culex mosquito 



Maggot of the flesh-fly 



Water boatman, or Corixa 



Fresh-water sow-bug, or Asellus. 

 All of these organisms are most abundant during the months of 

 June, July, and August, during which period they are also in greatest 

 demand by the bass culturist. While they are all utilized to some 

 extent, certain of the organisms are more acceptable to the fish and 

 are taken more readily than others. The mosquito and Mayfly larvae 

 and the small minnows are the forms most eagerly taken, while the 

 maggots and young sow-bugs are rejected at first but taken readily 

 enough when the young bass become accustomed to them. The Corixa 

 is taken readily by the larger fingerling bass. By the use of these 

 natural foods we find the bass can be trained to feed at a certain spot 

 with the same avidity as do trout. Experiments are now being con- 

 ducted to ascertain the possibility of rearing the fresh-water shrimp 

 (Gammarus fasciatus) in large enough quantities to be of importance 

 as a food for the young bass. 



Discussion. 



Mb. C. O. Hayford, Hackettstown, N. J. : At the Hackettstown hatch- 

 ery we have 164 trout ponds arranged in 17 separate parallel lines and 

 all are fed by spring water. They contain brook, brown and rainbow trout, 

 existing under identical conditions, and yet the mortality will vary widely. 

 The mortality record for the day may show one pond to be normal, a loss 

 of 40 in a second, 25 in a third, and 50 in a fourth. The reason for this 

 wide variation when the ponds and the fish are identical in all respects 



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