FOR PLEASURE AND PROFIT. 139 



should be about forty-five degrees, the time occupied will be 

 about eighty days. It is stated OIL good authority that 

 salmon ova have been known to hatch in thirty days, and 

 that they have taken as long as one hundred and forty days. 



If perfect cleanliness is observed, a. copious and pure 

 supply of water maintained, care taken to thoroughly impreg- 

 nate the eggs, and perfect quiet in the hatchery strictly 

 enforced, the work of incubation should proceed in a per- 

 fectly satisfactory manner. It is want of, or temporary 

 neglect of, these necessary precautions that causes trouble, 

 and, trouble having once originated in connection with the 

 operations, it may very easily prove disastrous. Fungus, 

 for instance, is quite easily prevented; but it is most 

 difficult to eradicate where it is permitted to occur. Even 

 where it is " cured/' the eggs or young fish once attacked 

 by it are never so strong again. 



After a little experience, you will be able at various stages 

 to calculate the chances of complete success at hatching time, 

 and to. distinguish between the fairly good and the very good 

 eggs, and to conduct your operations in accordance with 

 such discO'very. About half-way through incubation is the 

 first stage of the eggs becoming eyed, and they may now 

 stand very careful handling for the purpose of; examination. 

 All the unfertilised eggs will also be quite easily distin- 

 guished at this stage. When the eggs are " fully eyed " is 

 the time to transplant them to redds outside, after the 

 manner I have already described. In this way the stock of 

 eggs in the hatching boxes may be reduced one-half with 

 advantage. 



When hatching commences, fermentation will occur, and 

 removal of the shells demands attention; and now the 

 advantages of having at least one box in each row empty, 

 or the addition to the hatchery of a " washing " box, becomes 

 apparent. First the quantity of water flowing through the 

 boxes has to be increased, as I have already advised ; second, 

 the shells must be removed as soon as possible. The in- 

 creased flow of water will counteract fermentation ; but, in 



