IMPROVEMENT OF FISHERIES 231 



The trout angler would exterminate them, the 

 pike fisher preserve them. The ground, how- 

 ever, is easier here, because it is now generally 

 agreed that the best trout are found in lakes 

 containing pike, provided the water is of vary- 

 ing depths. Pike therefore are beneficial pro- 

 vided they are not allowed to get the upper 

 hand. Judicious netting of pike in Windermere 

 would therefore increase the number of trout and 

 raise the average size of the pike a consummation 

 which would satisfy both trout anglers and pike 

 fishers. 



Eels too are often exceedingly destructive, and 

 ought to be kept down. A single eel has been 

 known to devour 80 fry of the rainbow-trout in a 

 night. 



And then comes the most difficult problem of 

 all that concerning perch. Unless some check 

 is kept upon them they increase enormously 

 under favourable conditions. A perch^ of 3 Ibs. 

 2 ozs. was found to contain 155,620 eggs. There 

 are millions of perch in Windermere, and it is 

 common knowledge that it is almost impossible 

 to let down a bait anywhere in the lake without 

 immediately getting a perch upon it. And perch 

 in Windermere have not been netted for six or 

 seven years. They are annually decreasing in size, 

 and the drain upon the fish-food of Windermere by 

 these millions of fingerlings may, in a short time, 

 go far to ruin the lake. True, the perch-fry afford 

 food for the other fishes (in the fry stage both trout 

 and char feed upon them) ; but only pike tackle 

 grown perch. (The perch has a formidable dorsal 

 fin and knows how to use it with effect.) A 



