466 SALMON AND TROUT. 
or all of his fish whenever he wants them, and this can only 
be done by constructing a number of ponds. These may be 
round, or square, or any other shape, according to circumstances, 
and not larger than an acre in extent, otherwise they are difficult 
to net, and take too much time in running out. I prefer myself 
ponds of a quarter to half an acre for the yearlings, as the water 
can be run off in a few hours, the pond fished, and the water 
shut back ina day. This extent of surface exposed to the sun 
and air encourages a greater vegetable and insect growth than 
does a long narrow pond, and it is less easily ‘ poached.’ 
An additional security is to have the keeper’s house close 
to the water, and also to place obstructions, such as posts orna- 
mented with tenter-hooks, in the ponds ; poachers cannot afford 
to run the risk of confiscation or loss of nets more than once. 
All ponds, whether for business purposes or for sport, should 
be capable of being emptied at any time, and the greater num- 
ber of a pisciculturist’s ponds are of necessity drawn down 
every season in order to supply the demand for fish, and also 
to make certain that no fish remain in them. A few fish of 
half a pound amongst the fry will make all the difference in. 
the number of yearlings found, as I know from bitter ex- 
perience. One season a few yearlings were left behind in a 
nursery pond, and on the pond being fished the next season, 
these had nearly quadrupled their size, but at the expense of 
thousands of fry. Troutare cannibals, and will, unless provided 
with plenty of insect food, devour one another as long as there 
is any great difference in their size. This has been observed in 
the case of a few fish of only eight weeks old, which had been 
by accident put in a hatching trough amongst some fry of about 
five weeks old ; a comparative monster was seen with the tails 
of two younger fario sticking out of his mouth ; he was instantly 
captured, and when transferred to a basin in order to exhibit 
his amiable propensity, he disgorged one of his little cousins, 
half-digested, but the other disappeared down his throat! This 
propensity doubtless increases with age. 
T hold at the present time, devoted to the different varieties 
