130 FISH CULTUEB. 



CHAPTER VII. 



ON THE CROSSING OF BREEDS OF FISH. 



And now we arrive at aiiotlier valuable consideration 

 — that of crossing of breeds. There can be no doubt 

 mucb may be elicited here. In some rivers,- the race 

 of salmon and trout are naturally small, and without 

 appa;rent reason. In Scotland, for example, there 

 wUl be four rivers running into the same estuary, 

 and the breed, shape, make, and size of the fish of 

 every river will be distinct and different. In some, 

 the fish will be long and thin in shape ; in others, 

 short and thick. In some, they will scarce ever 

 exceed twelve or fourteen pounds in weight, and in 

 others they will run up to twenty, thirty, and even 

 forty pounds, if allowed to exist for a reasonable time. 

 Now, here it is evident that the rivers themselves 

 can have little or nothing to do with the growth of 

 the fish, since the great feeding grounds wherein the 

 fish grow and increase their weight, and that at a rate 

 out of all proportion to that of any other animal. 



