SPOTS IN WHICH SALMON DO NOT BREED. 191 



from reaching them. Such occurrences can very 

 rarely, if ever, take place in the spots salmon se- 

 lect for spawning. Those spots are in running 

 waters, where alluvial or other matter brous^ht 

 down by floods cannot well abide. And here let 

 me remark, that salmon never deposit their ova 

 in the sand or gravel of still, smooth, or deep 

 waters. They never breed in lochs or lakes. Nor, 

 a very curious fact, will they spawn in new gravel, 

 nor in gravel that has recently been disturbed by 

 natural, or artificial causes. For instance, a spate 

 or flood shall sw^eep away a portion of the gravel 

 of a ford, and, for many years, a favourite spawn- 

 ing locality, and by so doing expose a new stratum 

 of gravel. Not only will salmon spawn no longer 

 there, but they will not even rest in their journeys 

 in water having a bottom recently disturbed. A 

 period of about two years must elapse bofore they 

 will frequent a pool or stream from which gravel 

 has been removed, or to which gravel has been 

 added. So that an excellent spawning-bed, or a 

 famous pool may be annihilated by a furious rush 

 of water. 



Growth of Salmon-Fry. — The ova 

 having been hatched, the embryo salmon 

 pierces the sandy and gravelly crust of its nest, 

 and almost instanter assumes a shape somewhat 



