FISH NESTS. 23 



as in the case of the stickle-back, building a 

 true nest, or else depositing the eggs upon 

 the fronds and leaves of the plants, some 

 after the manner of insects. 



When the fish — I speak now of the salmon 

 and trout — are about to spawn, they set to 

 work and make their nest. They choose, 

 above all places, a shallow gravel bottom, the 

 reason being that there shall be a more rapid 

 flow of water, and hence a greater supply 

 of oxygen to the eggs themselves and also 

 to the young ones when born. The most 

 natural breeding-grounds for the salmon are 

 small, rapid, mountainous streams, deep pools 

 being in the neighbourhood, wherein they can 

 rest and take shelter. They, doubtless, 

 ought to have pools ; because, as I said be- 

 fore, a salmon does not deposit her ova at one 



