296 Salmon-Fishing. 



is cruel to the ova, it is not kind to the ascending 

 fish. Salmon do not incline to ascend a river 

 either when it is very low or when it is in very 

 high flood ; they prefer a happy medium. Now 

 we have seen that the effect of increased drainage 

 is to bring down the water more quickly and in 

 greater volume after rain, and to reduce it to a lower 

 level during drought. The time favourable for the 

 ascent of salmon is thus very considerably dimin- 

 ished, and the consequence is that they are often 

 detained too long in the tidal waters, where they 

 are either captured by the nets, devoured by their 

 natural marine enemies, or poisoned by the pollu- 

 tions of the river. Even should they escape these 

 risks and enter the fresh water, the river, especially 

 if it be obstructed by weirs, is no more favourable 

 for their progress than it was for their entrance ; 

 and the result is overcrowding in the pools, with its 

 attendant evils. A similar condition of affairs when 

 the fish are on their passage to the sea can only 

 lead to similar disastrous results. The increase of 

 hill-drainage may, so far as the fish are concerned, 

 be an irremediable evil ; but all the more on that 

 account should effective measures be speedily direct- 

 ed against those other evils, the removal of which is 

 both practically possible and reasonably desired. 



A new and more formidable enemy of the salmon 

 has appeared in the form of what is now known as 



