688 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



keep very close together, and sometimes they even gather into such a 

 dense heap that the lower ones are squeezed to death. 



In old-fashioned hatching apparatus, therefore, such gatherings of the 

 fish should, as much as possible, be prevented by moving the boards of 

 the lid and by changing the current of water. In the California and 

 Wilmot apparatus there is no danger of fish squeezing each other to 

 death, because the rising current of water makes such a gathering of 

 the fish impossible. For this reason alone apparatus with a rising cur- 

 rent is to be decidedly preferred. 



During the whole umbilical period the whole work of the piscicultur- 

 ist consists in constantly renewing the water and in removing any dead 

 or dying fish. In the California apparatus the inside boards can be 

 moved up and down from time to time, and thus any dirt gathered in 

 the grates can be removed. 



If the water is pure, and the young fish are strong and healthy, a 

 single man can superintend several millions of young fish during the 

 umbilical period. 



The umbilical bag grows smaller every day, and the little being, which 

 at first did not at all resemble a fish, gradually assumes the shape of a 

 fish. The body, in the beginning only a thin thread, grows thicker 

 every day ; the fins grow stronger -, the color, at first only a monotonous 

 pink, white, or orange, becomes more directly marked; dark cross- 

 streaks and reddish dots begin to appear, and the inner organs gradually 

 develop more and more. Finally the young fish is completely formed ; 

 it no longer rests quietly at the bottom, but rises to the surface and 

 meets the current ; it begins to snap after little particles floating about 

 in the water by making a pushing motion. The little fish hereby shows 

 its desire for food, and now is the most suitable time to place the fish in 

 open waters, or, at any rate, in larger boxes or tanks. This, in most 

 cases, finishes the work of the pisciculturist. 



There has been a good deal of dispute as to where it would be most 

 advantageous to place the fish after they have been hatched, and even 

 at this day opinions differ greatly on this point. As a general rule I 

 consider it best to place the young fish in open waters immediately after 

 the umbilical bag has disappeared, or, better still, shortly before it dis- 

 appears. My reason for this is simply this, that in a large piscicultural 

 establishment it is utterly impossible to feed and raise the young fish in ac- 

 cordance with the dictates of nature. By giving artificial food, either 

 ground brains, chopped meat, liver, blood, &c, the fish are easily tamed. 

 They forget — or rather they never learn — to seize their food,- which nat- 

 urally consists of living animals. In the narrow tanks the young fish 

 never learn to know their enemies, and consequently are not able to 

 escape the manifold dangers threatening them in open waters. 



Other experienced pisciculturists maintain that it is far more ad- 

 vantageous to keep the fish, if possible, for a whole year in inclosed 

 waters, and thus to let them outgrow the majority of their enemies. 



