46 THE SALMON FISHEK. 



the Pacific. Fish are continuously in large rivers 

 the whole year round that is, squads or individuals 

 are found but the great body of fish move together. 

 This principal movement, or migration, takes place 

 in the early autumn in most rivers, after the fall 

 rains swell their volume, for two reasons : first, 

 because it is near their true spawning season, and 

 second, because it is easier for them to surmount 

 falls, rapids and other obstacles when the river is full. 

 On rivers of extreme length, like the Columbia, 

 Yukon, Kuskokvim, and others of the Pacific coast, 

 the spring run of salmon does not go back to the 

 sea, for obvious reasons. If the fish have 500 miles 

 or more to ascend, they cannot' afford to lose time 

 by running in and out, for swift as their speed is in 

 long reaches of clear water, they cannot overcome 

 difficult obstructions without painful and repeated 

 efforts, often lacerating themselves most shockingly. 

 High falls especially retard their progress. To sur- 

 mount these they are obliged to climb their rugged 

 abutments, which are full of pockets and crevices 

 and projections, over which the lateral overflow is 

 constantly spilling in greater or less quantity ; and 



