; 54 



REPORT OF THE COMMISSIONERS OF 



dies in two minutes, and yet when the milt has been added to the pan of eggs a 

 little water is then added to both to make the zoosperms more active and the pan is 

 tilted from side to side that the eggs may draw in not only water, which plumps 

 them, but a spermatic particle as well. During the absorbing process when the 

 eggs are " set " by sticking to one another and to the pan, the eggs may be impregnated, 

 but not often absorption ceases, for then no power can fertilize the eggs if a zoo- 

 sperm has not found a micropyle. After tilting the pan to aid impregnation more 

 water is added and the pan of eggs is placed apart to separate, and this takes a 

 longer or a shorter time, depending upon the temperature of the water, say from 

 ten minutes to half an hour, separation meaning that absorption has ceased and the 

 eggs are free from one another. The eggs are then washed thoroughly, for an excess 

 of milt which will sour may cause fungus, and are ready to be placed on the trays in 

 the hatching trough. In this, the dry process, one hundred per cent of eggs can be 

 impregnated, if the eggs are all perfect, and it is common to impregnate ninety-five 

 per cent. In the wet process, practiced before Vrasski made his discovery, the 

 method was the same as the dry, except that the pan was first filled half full of 

 water. By the wet process fifty to sixty per cent of the eggs taken were 

 impregnated. 



With the eggs placed on the trays and running water provided in the hatchery 

 troughs, man is second to nature in their development. The dead eggs must be 

 removed, fungus guarded against, and care exercised that no sediment covers them. 

 The living enemies of trout eggs are not to be feared if the troughs are covered so 

 that they find no entrance. The eggs may hatch in 45 days, or they may require 

 more than 100 days (in Canada salmon eggs have been 210 clays in hatching), 

 the time being dependent upon the temperature of the water, as already stated in 

 the case of eggs deposited naturally. The young trout with umbilical sac attached 

 is called an alevin ; if one wishes to be very precise and distinguish this stage from 

 the next, when the sac is absorbed and the little fish becomes trout fry. During this 

 period the alevin is sustained by absorbing the yolk sac, but before it is entirely 

 absorbed it begins to feed through the mouth, and if the fish are to be planted in 

 wild waters as fry, this is the time to make the plant, that the fry may early become 

 accustomed to their new home and the food it contains. The fish are very hardy at 

 this period and bear transportation well. As alevinsthe little trout gather in masses 

 in their endeavors to hide or get under something which will cover them, and if the 

 construction of the troughs would permit many would smother, but as the crowding 

 is chiefly to avoid the light the boxes or troughs are covered to exclude it, and cause 

 the little fish to separate. 



