REARING 181 



tected from the attentions of ' Fur, Feather, and Fin, 1 

 also from Jack Frost, and (need I add ?) sewage. 



An arrangement of perforated zinc screens at the 

 inlet and the outlet, on the principle of a hatching- 

 box, should be provided, and of course there must be 

 a cover. 



A specially constructed wooden ova-bed can 

 sometimes be used with advantage. As soon as the 

 alevins have begun to feed, the outlet screen is 

 removed and they are allowed to work their way down 

 the stream at their leisure into the water which they 

 are intended to replenish. 



Under such a system as this the percentage of 

 loss, which is of necessity very heavy, is anticipated 

 and to some extent discounted by the very large 

 quantity of eggs laid down. It is, however, only 

 under exceptional circumstances that the plan of 

 sowing eyed ova in artificial redds can be adopted 

 with advantage and economy. And you may well 

 pause to take advice before incurring any heavy 

 outlay about artificial ova-beds. 



THE ALEVIN STAGE 



If you have been expecting to see a completely 

 developed fish emerge from the shells, you are now 

 disappointed. The new-born creatures are in the 



