NATURAL HISTORY OF THE SALMON, 11 



up the rivers to breed, no young fry can come 

 down the rivers to enter the sea, and there to grow 

 into adults; consequently, there can be no in- 

 crease, and if no increase, there must speedily 

 be extermination. 



There is, however, one of the habits of the sal- 

 mon on which it is necessary to say a few words, 

 as bearing upon the present subject, in order to 

 show and to establish the detrimental effect of 

 impenetrable barriers across rivers, either by weirs 

 or otherwise. Dr. Turner says, " when it so hap- 

 pens that their passage is effectually obstructed^ they 

 soon grow lean and sickly, and in a year or two 

 pine away and die." This can be but an opinion, 

 though, perhaps, founded upon good grounds ; but 

 it is an opinion so reasonable and so conformable 

 to the nature of the fish, and, by analogy, to the 

 nature of all other animals, that it contains, if not 

 positive, at least presumptive evidence of its ac- 

 curacy. We all know the irresistible instinctive 

 purposes of this fish to get up into the rivers ; 

 their wonderful efforts show it. We all know that 

 it is only in the sand-beds of rivers that the fish 

 can spawn, and they know it at the least, as well 

 as we do. If, therefore, they are thus thwarted in 

 complying with the dictates of instinct, which never 

 misleads or deceives, it is most reasonable, if not 

 conclusive, to infer, that they do, as Dr. T. says, 

 " pine away and die ;" for a salmon, as is observed 

 before, being both a salt and a fresh water fish, can- 

 not live without having access to both : if he is de- 



