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204 A FISH FARM. 
the necessary chemical elements which are being constantly 
exhausted by the respiration of the fish. 
The water enters each pond through a plank trough, the 
sides of which are sunk nearly to the level of the ground. 
These troughs are fifty feet long and three and a half feet 
wide, and are filled to the depth of six inches with coarse 
gravel, over which there are six inches of water flowing with 
a slight eurrent'to the ponds. As it is the habit of the trout 
to soni shallow running streams to spawn, they eagerly re- 
sort to these spawning ways when ready, and are taken by 
closing the bottom of the way, and driving the fish into à 
bag net at its entrance into the pond. They are then re- 
moved in tubs of water to the hatching house, for the pur- 
pose of taking the ova from the female and impregnating 
them with the milt of the male fish. The modus operandi 
is as follows : The female fish is grasped with one hand by 
the back and shoulders, the vent being held under the sur- 
face of the water in a tin pan or other vessel partly filled, 
while with the other hand the abdomen is gently rubbed or 
pressed toward the vent. If the ova are mature and ready 
to be shed, a slight pressure is sufficient to extrude them. 
The same operation is then gone through with the male; if 
his milt is mature, it will ow i in a small quantity into the 
vessel. A few drops are sufficient to impregnate thousands 
of eggs. The milt and the ova are then gently stirred to- 
gether, and allowed to remain undisturbed for five or ten 
minutes. The water is then poured off, new water is gently 
admitted to wash the eggs, and they are n to be placed 
in the hatching troughs. 
It may be as well to state here that the spawning time 
` for trout is from October till March, the principal spawning 
months being November and December. It is generally cal- 
culated that a trout weighing one pound will produce 1000 
eggs ; the larger and smaller ones in the same general pro- 
portion. 4I Nds known, however, during the past season. 3 
trout of less than half a pound in weight, to deliver 1000 
eggs by actual count, 



