126 Modern Fishculture in Fresh and Salt Water. 



little eyes, and its size tested by half as many heads; 

 and if water flows through it, they are very apt to fol- 

 low, no matter where it may lead, nor whether return is 

 possible. The instinct of a trout impels it to jump at a 

 fall or in going up stream, hence provision must be 

 made to stop them from leaping over the inlet screen by 

 a projecting board or other device, more especially in 

 the fall of the year, when they wish to ascend to the 

 upper waters to seek suitable places for spawning. 



If the fry are kept for the first nine months or a year 

 in "rearing boxes," it is not so hard to confine them as 

 it is in the outdoor ponds, where the woodwork has to 

 be fitted into the earth ; and this system has its advan- 

 tages, which are security of confinement, compactness, 

 the ease with which they can be inspected and the larger 

 ones removed from their weaker brethren, and the pro- 

 tection from bird, beast, reptile and insect enemies to 

 which their relatives in the outdoor pond are exposed. 

 To counterbalance these advantages, we have in the 

 rearing boxes more care and labor, and less natural 

 food. Still, if the labor can be given, it is the surest 

 way, for the first three months at least, after which time 

 they are better able to stand the exposure of outdoor 

 ponds and avoid their enemies, which decrease in num- 

 bers with increasing size. 



There is always one fence in summer time which de- 

 tains the trout more effectually than any screen. This 

 is the stream of warm water which the trout brook emp- 

 ties into, and, although they may seek its depths for 

 food in winter after running down oflf the spawning 

 beds, the first hint of a rising temperature sends them 

 back to the cooler spring waters. 



A good self-cleaning screen for large trout is a re- 

 volving cylinder of wire cloth. Make disks of eighteen 



