PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1922. 23 



large numbers. It is of much interest, however, in connection with 

 the suggested possibilities as to its value in stocking lakes and 

 streams with eyed eggs rather than the more expensive fry or finger- 

 lings. 



The available information on the subject indicates that prac- 

 tically perfect results, in so far as incubation is concerned, may be 

 expected from eyed eggs of the trouts or salmons when planted in 

 the deep gravel bed of a suitable stream where a substream flow or 

 spring seepage is present, and one of these conditions doubtless al- 

 ways obtains in a stream flowing gently over a bed of deep gravel. 

 Trout or salmon spawning naturally in streams invariably seek 

 such places, and trout spawning in ponds will seek seeping water, 

 either in the nature of spring seepage entering the pond or water 

 seeping from the pond through a porous section of its bottom. 

 Observations made during the summer of 1921 of a number of plants 

 of eyed eggs of the black-spotted trout in the Belcher River and 

 tributaries, in the Yellowstone National Park, under the conditions 

 named above, revealed a 100 per cent hatch in each instance, and the 

 resulting fry were uniformly strong and vigorous. They displayed 

 all the tendencies of naturally hatched fish, burying themselves in the 

 gravel to a depth of 8 or more inches and remaining there during 

 the time required for the absorption of the umbilical sac. The evi- 

 dence at hand would indicate that eggs planted in a dead pond bot- 

 tom result in total failure. If this method of stocking streams and 

 lakes can be carried out as successfully as now seems possible, it will 

 offer in innumerable instances many advantages over present meth- 

 ods. It will permit of making plants at the headwaters of streams 

 or of the tributaries of lakes, always a desirable location, though 

 inaccessible with fry or fingerlings, and of making distributions over 

 a greater water area. It will also materially reduce the costs of dis- 

 tribution and hatchery expenses. 



METHODS OF PLANTING EYED EGGS. 



In making plants of eggs in the bed of a stream it is impossible, 

 because of their buoyant tendency and the action of the current, 

 simply to scoop out a "nest," deposit the eggs therein, and coyer 

 them with gravel. Several ways have been resorted to in making 

 such plants. A method employed on the Pacific coast is to place the 

 eggs to be planted in alternate layers with gravel in a box or can — 

 a 5-gallon coal-oil can is mentioned. An excavation of sufficient 

 size and depth is made in the gravel bed at the site selected and 

 the can is carefully inverted into it, allowing its contents to settle 

 into the excavation. In other places two pieces of board or plank 

 are fastened together to form a V. This is placed in the stream with 

 its apex against the current. The " nest " is then made in the eddy 

 or slack water in the angle of the V. 



ACCLIMATIZATION. 



Throughout the history of practical fish culture numerous instances 

 are to be noted of the successful establishment of nonindigenous 

 fishes in various parts of this country and also in many of the for- 

 eign countries. In most cases such transplantings have resulted in 



