On Stocking: \ 5 



surface if they are merely to be retained until the 

 absorption of the yolk-sac. But this space is 

 sufficient for double that number of eggs ; there- 

 fore there can be no real inducement to design 

 hatching trays to incubate an excessive number 

 of eggs in the smallest possible space. However, 

 the practice of over- crowding trout and salmon 

 eggs is general, and to this practice many of the 

 disappointments encountered in private hatcheries 

 are due. If the eggs are so incubated that a cur- 

 rent of water perpetually cleanses each egg during 

 the whole process, strong fry is the result ; if not, 

 the contrary obtains. 



APPROPRIATE EMPLOYMENT OF OVA AS A 

 MEANS OF STOCKING. Ova is now generally for- 

 warded 011 the point of hatching, and for those 

 who have troughs suitable for rearing alevins to 

 the feeding stage, or fry for four or five weeks 

 longer, nothing can be better than fully eyed 

 Ova laid on temporary trays, or on the bottom of 

 the trough. Only if fully eyed Ova is laid on the 

 bottom of the troughs, certain precautions are 

 necessary, as the embryo is very easily suffocated 

 drowned in fact in still water. These precau- 

 tions are first, to spread the eggs evenly so that 

 no eggs lie on the top of others, or even touch 

 others latterly ; second, to lower the surface of 

 the water to within an inch of the eggs ; and 



