Histoiy and Habits 29 



when visiting fresh water always return to the 

 rivers in which they were spawned. They proba- 

 bly do so when nothing interferes to prevent ; but 

 when, from various causes, they cannot get into 

 their native streams it would certainly be natural, 

 if not unavoidable, for the gravid fish, whose first 

 instinct is to reach a place where they can deposit 

 their spawn, to go to some river they could ascend 

 if the entrance to their native one was practically 

 closed. An excessive number of nets at the 

 mouth of a river may cause salmon to desert it 

 while thus obstructed. For several years of my 

 acquaintance with the Restigouche River the 

 white porpoises have been in such great quanti- 

 ties at its mouth as to drive off the salmon of the 

 earlier runs, which undoubtedly went to rivers on 

 the other side of the bay. In 1896 there was a 

 run of large fish in the middle of July in the Res- 

 tigouche which were very different in their appear- 

 ance from the natives of that river, being shorter, 

 thicker, especially at the base of the tail, and with 

 much broader tails for the size than were found 

 in the Restigouche fish. They came in the river 

 all together and were past the lower waters, in two 

 or three days, — I took half a dozen of them, all 

 from twenty to twenty-five pounds, — but they did 



