FOODS FOR YOUNG SALMONOID FISHES. 



J* 



By CHARLES G. ATKINS, 

 Superintendent United States Fisheries Station, East Orland {Craig Brook), Me: 



In laying out schemes for the feeding of Salmonida, as well as most other 

 fishes, it is to be borne in mind that they are by nature dependent for nourish- 

 ment on living animals. Any departure, therefore, from a live-food regimen 

 must be regarded as having the presumption against its entire suitability ; and the 

 general experience of fish culturists tends to the conclusion that even so slight a 

 departure from nature as the substitution of the flesh of mammals for the natural 

 food is followed by deterioration in some of the most important functions of 

 the fish. 



Perhaps the function most seriously affected is that of procreation. It 

 has been found that fishes which have been reared on mammal flesh in artificial 

 inclosures do not produce offspring of normal vitality and vigor, and while the 

 possibility of there being other important factors in the case has not yet been 

 disproved it is the consensus of opinion that the deterioration observed is due 

 mainly to the unsuitability of the food. The view taken of this matter by the 

 best German authorities is well expressed in the concluding chapter of a serial 

 treatise on the feeding of salmonoids by the editor of the Allgemeine Fischerei- 

 Zeitung, January i, 1907, as follows: 



Assuming that the fishes grown in a wild natural state have the healthiest offspring, 

 it follows that for breeding fishes under all circumstances live natural food is the most 

 suitable. * * * There is a large list of fish breeders who reject wholly the feeding 

 of breeding fish and for egg production use v?i\A fish only. For brook trout this is 

 beyond doubt the correct standpoint, and it would be also for the rainbow and American 

 brook trout if we could get wild fish enough to supply the demand for eggs and fry. As, 

 alas, we can not get them, whoever wishes to breed these fishes must of necessity resort 

 to artificial feeding of breeders. 



The experience of American fish culturists will support this view. 



Under these circumstances it behooves us to look for food supplies as near 

 to nature as possible, and a conviction that duty leads in this direction has 

 been the inciting motive to the efforts at the Craig Brook station to produce 

 some living insect food which could be substituted for the chopped liver and 

 lights from slaughterhouses and the flesh of old horses, which have been the 

 main dependence thus far. 



B. B. F. 190S— Pt 2— II g 



