296 SALMONIA. 



it continues, because fish change their stations 

 occasionally, and pricked fish sometimes leave 

 their haunts, which are occupied by others ; 

 and graylings are more disposed to change 

 their places than trouts. 



As instances of the difference in this respect 

 between large and small rivers, I may quote 

 the Vockla and the Agger in Upper Austria. 

 The first of these rivers, when I fished in it 

 in 1818, was full of trout and grayling, and I 

 believe I was the first person, for at least many 

 years, that had ever thrown an artificial fly 

 upon it. It is a small stream, from eight to 

 fifteen yards wide, and can every where be 

 commanded by the double-handed rod, and is 

 generally shallow. The first day that I fished 

 in this stream, which was in the beginning of 

 August, at every throw I hooked a fish, and 

 I took out and restored again to their element 

 in the course of a few hours more than one 

 hundred and fifty trout and grayling. The 

 next day I fished in the same places, but with 

 a very different result : I caught only half a 

 dozen large fish: the third morning, going 

 over the same ground, I had great difficulty 



