How to obtain it 181 



creeping things found at the bottom of our streams, almost without 

 exception, prey extensively upon trout ova. Every fish culturist 

 has found these creatures at some time or other coming down into 

 his hatching boxes. The filters will not keep them out. They 

 are so minute, in their early stages, that they are practically 

 invisible, and they get in unobserved, and then grow so fast that 

 soon they cannot get out again. In a well managed hatchery, 

 however, the trouble arising from this cause is trifling. But in a 

 stream, matters are very different. There are creatures innumer- 

 able, all instinctively attracted to the place where the eggs are 

 deposited caddis worms, creepers, shrimps, beetles, frogs, mice, 

 rats, ducks and other fowl, eels, trout, grayling, salmon, sea trout, 

 and nearly every other fish found in the streams. Nearly every- 

 thing ranks as an enemy to trout ova. Therefore it is apparent, 

 that by protecting the eggs, we are doing a great deal. But we are 

 doing more, for the artificial beds shelter the " alevins " for awhile, 

 and after they drop down the little artificial stream they are still 

 shielded from the bulk of the dangers enumerated, especially from 

 the depredations of trout and other fishes. 



The streamlet used as a hatching bed should be so constructed 

 that no outsider of the trout family can by any possibility get into 

 it. Eggs, before hatching, have no power of protecting themselves, 

 or of getting out of the way of danger. As soon as the embryo is 

 out, it at once possesses some power of self-protection. It has a 

 pair of well-developed eyes, and knows how to use them, and 

 immediately that wonderful power called instinct causes it to seek 

 a hiding place. So strong is this desire to hide, that if the little 

 creatures cannot find any other place they will hide under each 

 other, and in doing this they gather together in dense masses, 

 reminding one of a swarm of bees. 



Californian baskets, which are simply wire cages in which 

 eggs are piled one above another, do not suit the eggs of our 

 British Salmonithz, It is true that by using them a large number 

 of eggs can be hatched in a small space, but the result is undoubt- 

 edly a partial suffocation of the embryos, and a general weakening 

 of the young fish, They may do well in America, but what will 

 suit the fish of one country often may not agree with the fish of 

 another. A lower prevailing temperature is, no doubt, to some 



