History and Habits 35 



any, is imperceptible. Unless the fry of the Res- 

 tigouche salmon put in the head waters of the 

 Upsalquitch and remaining there till they attain 

 smolthood obey some inherited instinct, and on 

 their return from the sea pass by the mouth of 

 the Upsalquitch and continue up their ancestral 

 river, it is proof that they are subjected to some 

 conditions at sea which prevent their attaining 

 the size of the fish from which they descend. It 

 is quite probable that there are conditions of feed- 

 ing ground at sea which affect the growth of 

 salmon, causing those of some, and frequently 

 neighboring, rivers, to vary materially in size. I 

 know of no case of a salmon river having the 

 character of its fish changed by stocking it with 

 fry from elsewhere, though perhaps the experiment 

 has not been tried often and intelligently enough 

 to get many specific facts on the subject. It 

 seems, however, that it can be nothing else than 

 a question of food, and that fry from a river pro- 

 ducing small fish, if put in a stream which yielded 

 large ones, would grow to be big salmon, and 

 vice versa. 



Other theories as to the food of these fish are 

 quoted by Mr. Pennell, and it is certain that both 

 here and in Britain the salmon, as they approach 



