238 PROPAGATION OF FISH. 



trout suffer most and die the first, at least wlien they are 

 confined in a limited space with a small flow of water. 



The first point in fish culture is to obtain the spawning 

 fish in proper condition, for if the eggs are not mature or 

 ripe, as it is usually called, not only are they useless, but 

 the effort to extract them will kill the parent. Fish 

 breeders, who make the cultivation of trout a business, 

 and there are many in this country, keep on hand in suit- 

 able ponds a supply of large fish. These arc taken from 

 the rivers, which they are ascending to spawn, and are 

 kept over from year to year. Connected with the ponds 

 in which they are confined, is a raceway, or long narrow 

 trough which has a gravelled bottom, is covered with 

 boards to exclude intrusive eyes, and in every way is 

 made as attractive a nesting spot to the fish as possible. 

 Into this they will proceed of themselves when they are 

 ready to perform their allotted act of reproduction, and 

 the breeder awaiting his opportunity, places a net at the 

 mouth of the race and frightening them in, selects such 

 as are ready for manipulation. 



When in a perfectly ripe condition, the eggs lie free in 

 the ovaries in the abdomen, and may be extruded by a 

 gentle pressure downward along the sides of the fish. 

 They are caught in a basin and are vitalized by coming 

 in contact with the milt from the males, for the fish, male 

 and female, are stripped indiscriminately into one common 

 receptacle. Formerly, the practice obtained. of having 

 this basin full of water, under the idea that such arrange- 

 ment more nearly reproduced the natural conditions, but 

 subsequent discoveries led to a change of this method. The 

 ova are fertilized by the spermatozoa of the milt entering 

 through the micropyle, and it was ascertained that these 



