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When salmon are swimming in the river Tweed up 

 stream, it has been estimated by experienced anglers that 

 they travel at the rate of about two miles per hour. 



Salmon, in descending the river after spawning, are 

 generally emaciated and exhausted. Many, apparently 

 hardly able to swim, float down the stream to the sea. 

 Every spring, large numbers are found dead at the sides 

 of the river, or in pools. 



What causes the migration of salmon is matter of con- 

 jecture. I have observed, when walking along the Ber- 

 wickshire coast, salmon leaping frequently at or near the 

 mouths of small rivers or streams ; and it has occurred to 

 me that, as they must get into rivers for spawning, instinct 

 induces them to seek those rivers the waters of which they 

 find most suitable for the purpose. 



Certain it is that salmon, after having frequented 

 particular rivers from time immemorial, have abandoned 

 them, and the inference is that they betake themselves to 

 other rivers which they deem preferable. 



As an example of this, I may refer to the river Whit- 

 adder, which has a course of about forty miles from the 

 Lammermuir Hills. This river joins the Tweed, at a dis- 

 tance from its mouth of about three miles ; so that all 

 the salmon caught in the higher parts of the Tweed must 

 have passed the mouth of the Whitadder. The tide flows 

 into it, as well as into the Tweed, flowing up the latter, 

 for six or seven miles. Formerly the true Sahno salar 

 frequented the Whitadder ; but during the last thirty 

 years no salmon of that variety has been seen in it. It 

 is frequented only by bull-trout. 



Reference may also be made to the Thames and to the 

 Coquet (Northumberland), both of which rivers used to be 

 frequented by the true salmon. I might also quote the 



