American Fislieries Society 83 



supply of this natural food, the problem of fry-feeding would be 

 solved. But in spite of all the numerous attempts which haAe 

 thus far been made to breed natural food in an artificial ■^ay in 

 considerable quantities, no one has yet got to the poin* of hav- 

 ing this food in sufficient quantity available at all times. Still, 

 this food plays such an important part in fry-feeding t];;'t Ave 

 must speak of the methods of its production. 



For the feeding of salmonoids, without doubt the artifi-ial 

 culture of amphipods ( Gammarus &c.) stands at the head. For 

 of all living food-animals that are to be considered for trout nnd 

 their relatives, the amphipods are least dependent in their re- 

 production on temperature, and can therefore be bred in winter 

 or in the cold spring months. 



The common amphipod (Gammarus pulex is doubtless 

 meant) has, as an inhabitant of cool trout-brooks, become so 

 adapted to low water-temperatures that it reproduces at all sea- 

 sons of the year To propagate them on a large scale the best 

 way is to lay out small ditches not over one meter (39 inches) 

 wide and 20 to 30 centimeters (8 to 12 inches) deep, with pools 

 a meter square here and there, say every 5 meters (15 ft.) These 

 ditches are to be thickly planted with water-cress and have a 

 strong current of water passing thru them. 



Amphipods are fond of flesh-offal. So, small morsels of 

 finely cut slaughter-house offal are thrown into the ditches, with 

 care against excess, since any considerable development of putres- 

 cence must be avoided. The amphipods of the trout-brooks have 

 great appetites for oxygen and do not well stand water that is 

 polluted by putrescence and poor in oxygen. 



These ditches are stoekt with amphipods from a trout-brook 

 where they have been collected with a dipnet. Here, after a 

 while they will multiply so enormously that a great deal of fry- 

 food can be taken out. Of course, for the fry only the very 

 smallest young amphipods can be used. So the contents of the 

 net with which they have been dipt from the ditches must be 

 strained thru a wire strainer thru whose meshes only the young 

 amphipods, the size of one millemeter (1-25 inch), can pass if 

 they are to be fed to the youngest fry. 



With the growth of the fry one can, conformably with nature, 

 also feed the somewhat older and larger specimens, while the 



