236 FLY FISHING AND SPINNING 



up-stream run. Not only has he to elude the wiles of the 

 fishermen and the onslaught of the otter, but he has to 

 fight against the bewildering turmoil of the rapids, and the 

 more deadly and difficult ascent of the falls down which, 

 as a smolt, he was carried a few months before. It is here, 

 faced with the thundering fury of the towering fall, that the 

 difficulties and dangers of the journey culminate. It can 

 only be this ever-compelling instinct which nerves him 

 to encounter such dangers, and which also prompts the 

 tremendous effort, and indicates the only place in the 

 descending waters which he must strike in order to gain 

 the haven above. 



But with the grilse or the salmon the attempt is made, 

 and though some may be killed and others stunned and torn, 

 yet the rest conquer, and instances of the survival of the 

 fittest are soon proceeding on their way up-stream. It is 

 on this upward journey that the grilse of four pounds may 

 perchance pass the smolts of three ounces members of his 

 own redd and hatched from the same batch of eggs on their 

 way down to salt water. 



THE RETURN WHEN INJURED 



When hurt in his upward course to the spawning grounds, 

 instinct again impels immediate action. Stronger and 

 more imperative than spawning is the instinct of self- 

 preservation. Fatal would be a stay in fresh waters with 

 that gaping wound in his silvery side, for most assuredly 

 would the zoospores of the dreaded saprolegnia enter the 

 abrasions in his skin, and speedily destroy him.* It is only 



* The Saprolegnia ferax, the fungus mentioned above, is said by Mr. J. 

 Hume Patterson, in " The Cause of Salmon Disease " not to be the fungus of 

 the salmon disease, the latter being due to a different bacillus the Bacillus 

 salmonis pestis which taking advantage of wounds or abrasions in the exo- 

 skeleton of the Salmon, bores its way into the tissues of the epidermis, and 

 dermis. It appears to be carried by the water and to affect fish other than 

 salmon. 



