HATCHING TEOUT 143 



have been submerged in the troughs. Daily 

 picking is desirable, but not always imperative. 

 The temperature of the water, and the fish- 

 culturist's knowledge of its liability to produce 

 fungus, must help him to decide this matter. 

 In very cold water fungus develops very 

 slowly, but in rising temperature more rapidly ; 

 it is also more likely to appear in abundance in 

 hard water than in soft water of the same tem- 

 perature. The appearance of dead eggs does 

 not always mean that they were not fertilised. 

 Their death may have been caused by careless 

 handling, by being jarred or bruised, notably 

 by instruments used in picking. It is to reduce 

 the possibility of injury by picking, that the use 

 of the rubber bulb is advocated instead of the 

 old-fashioned picker employed in many hatch- 

 eries. 



When trout eggs are carefully fertilised, and 

 water conditions remain normal, there is not 

 likely to be a very heavy loss. Occasionally 

 something that cannot be foreseen nor pre- 

 vented happens which results in an abnormal 

 death rate among the eggs, sometimes forcing 

 the employment of extra labour in order to clean 



