THE GAME BREEDER 



143 



(after five or six days feeding of raw 

 liver alone to newly hatched fry) the 

 fresh liver and meat should be thoroughly 

 ground together with from one-fourth to 

 three-fourths of its weight of wheat mid- 

 dlings. The middlings, in itself good 

 food which will sustain fish indefinitely, 

 is particularly valuable in absorbing and 

 holding the juices of meats and makes 

 a mixture of about the right consistency 

 and gravity to remain in suspense or 

 slowly sink in water, while it is easily 

 distinguished by the fishes once they are 

 accustomed to it. It is a cheap and gen- 

 erally available staple. Food prepared 

 as described may be readily dried and 

 preserved for emergencies where a fresh 

 supply of meat is lacking. 



That millions of trout and salmon fry 

 . have been and are being maintained in 

 overcrowded hatching troughs upon a 

 diet of beef liver would appear to be 

 positive evidence of its great value, while 

 it is commonly as easily and cheaply ob- 

 tainable as any form of animal food. 



The chief object of this paper, how- 

 ever, is to suggest that young salmon and 

 salmonoids reared in captivity should be 

 given the minimum quantity of artificia 1 

 food and a maximum area and flow of 

 water containing their natural food, for 

 which they should be permitted to forage. 

 Prepared food should supplement the 

 natural supply where water area is over- 

 crowded with young fish, or where 

 drouth, cold or other climatic conditions 

 interfere with the normal natural supply. 

 In support of this view is offered the 

 following summary of well-known or 

 readily ascertained facts and examples : 



1. That along the salmon rivers and 

 trout streams fry existing under natural 

 provisions are commonly in excellent 

 physical condition, mortality among them 

 being mainly caused by abnormal disturb- 



ances of the nests, such as floods, drouths 

 or extraordinary climatic changes, or by 

 the depredations of natural enemies, 

 birds, reptiles and other animals. 



2. That salmonoids are not surface- 

 feeding fishes exclusively, but seek food 

 suspended in the water and on the shores 

 and bottom surfaces accessible to them; 

 and that of necessity they must collect 

 more or less vegetable and sedimentary 

 matter; in fact, that they are rather om- 

 nivorous than piscivorous or carnivorous 

 fishes. 



3. That under normal natural condi- 

 tions a continuous succession of season- 

 able aquatic and insectiverous foods, 

 much of which will embrace vegetable 

 matter in some form, is supplied to the 

 young fish. 



4. That owing to the minute particles 

 of food matter collected by newly 

 hatched salmonoids, it is doubtless im- 

 possible to distinguish with accuracy the 

 natural or instinctive selections made by 

 them, or to determine nutritive values. 



5. That it will appear that suitable 

 natural food for salmonoids is abundant 

 in the waters wherever trout and salmon 

 spawn, and that the most available, 

 economical and scientific provision for 

 young salmonoids may be made in the 

 preparation and adaptation of sufficient 

 w r ater area in normal natural condition, 

 but subject to control as regards floods, 

 drouths, freezing to extremes, and the 

 exclusion of destructive animals. Con- 

 trolled areas of stream or prepared runs 

 should provide for the absolute regulation 

 of the water flow, and should contain 

 trap pools or other devices for collecting 

 the fish, excluding them at the end of 

 the spawning season, and finally reducing 

 the flow of water to a minimum for the 

 purpose of capturing the fry or young 

 as may be desired. — Bulletin of the 

 Bureau of Fisheries. 



