258 How to obtain it. 



The fish will now do very much of this work by disturbing any 

 deposit and sending it on to the screen, whence it may be raked 

 out ; indeed, they often scour the bottom pretty well. There is a 

 good deal of material to settle to the bottom, such as the sediment 

 brought down by the current, dust from the atmosphere, splash- 

 ings from heavy rains, the excrement from the fish themselves, 

 etc., and care should be taken that masses of filth do not 

 accumulate unduly. These matters are easily kept right by 

 constant attention from the beginning, but should accumulations 

 be carelessly allowed in the ponds, wholesale disaster may be the 

 result. 



I have sometimes been asked whether yearlings reared in 

 ponds and then turned out can hold their own against the wild 

 fish. Undoubtedly they can. I have tried many experiments by 

 way of testing this, and am quite satisfied about it. Should any- 

 one have any doubt on the subject, nothing is easier than to place 

 a few large trout for a short time amongst any yearlings to be 

 turned out. The latter are soon educated, for they value dear life 

 more than might be supposed. 



I turned a number of yearlings into a pond in a natural 

 stream which flows close by my writing room, and as I now sit 

 writing this, I can see what goes on in that pool. There was one 

 big trout in it. The yearlings when once fairly settled took up 

 their positions, and waited for anything in the shape of food that 

 was brought down by the current. The big trout did the same, 

 and I saw him several times make an attempt upon the life of one 

 or other of the yearlings, but the way in which these eluded him 

 was instructive. They were together in this pool for some days, 

 but nothing serious seemed to happen till a flood took place, 

 during which the big trout disappeared, but the yearlings still 

 held their own, with an accession to their numbers. They might 

 or might not be the same fish that were in the pool before, but 

 there they were. 



Yearlings are at first largely fed in the ponds by means of the 

 feeding box described for fry, the only difference being that the 

 perforations at the bottom of the box are larger. Some of them 

 will, however, take sufficiently large pieces of meat by July or 

 August to make it safe to throw the food with the hand, and as 



