310 ZOOLOGY 



Besides the smelt there are, in this family, numerous impor- 

 tant species. The salmon proper ' are restricted to the north 

 temperate and arctic regions, and live cither in the sea, migrat- 

 ing to fresh water to spawn, or exclusively in brooks and 

 lakes. The migrations of sabrion from the sea up the rivers 

 are remarkable. Hundreds of miles are sometimes journeyed, 

 rapids swum, and falls leaped, for the purpose of lajdng eggs 

 in some remote lake. At the end of their journey the eggs 

 are laid and male and female parents die. On the Atlantic 

 coast the Penobscot River has the most unportant run of 

 salmon. The Pacific salmon pass up the Sacramento and 

 Columbia rivers, and up manj^ rivers of British Columbia and 

 Alaska. In these rivers the fish are caught as they ascend to 

 breed. Such is the greediness and lack of foresight of the 

 canning fisheries on the Colmnbia River that very few salmon 

 are permitted to pass the nets of the canning factories, and 

 consequently the apparently inexhaustible supply of this fish 

 has been immensely reduced and threatened with destruc- 

 tion, but it will probably be preserved liy the assistance of 

 artificial hatching. 



The trout, of which there is a number of kinds on both 

 continents, is commercially much less important than the 

 salmon proper. As a result of overfishing, and the pollution 

 of streams Ijy factories and sewage, this fish is disappearing 

 from Eastern waters. 



The whitefish, of which we possess many species, is exclu- 

 sively an inhabitant of fresh water = and is derived chiefly from 

 the Great Lakes. Its teeth are almost com]:)letely absent, or 

 very small ; it feeds almost exclusi^-ely upon small arthropods 

 and mollusks. It is of very great connnercial importance, 



' Fig. 2S4. 2 Fig. 2S8. 



