ARTIFICIAL, PROPAGATION OF TROUT. 9 



The fish usually pair on the nests, the males fighting viciously for 

 the jDossession of the females. A few eggs are deposited at a time 

 by a female and fertilized by the milt which the male simultaneously 

 deposits. This process of spawning and impregnation by a pair of 

 fishes is repeated man}^ times until all the eggs have been deposited, 

 and through the constant working of the fish on the beds the eggs 

 become buried in the gravel. After a spawning bed is once occu- 

 pied it is hard to drive the fish awa}^, the female, especially, returning 

 to it desj)ite all hindrances. A female taken from her nest, marked, 

 and placed in the water a mile downstream was found occupying the 

 nest the following morning. The males remain on or near the beds 

 for* some time after the last females have spawned and left. 



CHARACTER OF THE EGGS. 



Brook trout eggs will average about one-sixth of an inch in diame- 

 ter, but there is a great variation in the size of eggs taken from fish 

 of difi^erent localities. Frequently lots are found of which little 

 more than 300 eggs are required to make a fluid ounce, while other 

 eggs are so small as to measure TOO to the ounce. Fish-culturists 

 favor the larger eggs, as it is generally believed that they produce 

 stronger and better fish than the smaller ones. The time necessary 

 for developing the eggs is dependent on the temperature of the 

 water, vaiying from about 125 days in water at 37° F. to about 60 

 days in water at 50° F. 



PROPAGATION. 



The first attempt to artificially propagate trout in America was 

 made in Ohio in 1853 with marked success. Further satisfactory 

 trials were made in 1855 and 1859 in Connecticut and New York, and 

 in 1864 a hatchery was established in New York which carried on 

 the work on a large scale. Somewhat later trout propagation was 

 taken up by other State authorities and by the Federal Government, 

 and it is now extensively conducted in many parts of the country. 



WATER SUPPLY. 



In selecting a location for a trout hatchery the first consideration 

 is an amj)le supply of suitable water so situated with reference to 

 the proposed hatchery that it can be brought completely under con- 

 trol. In this matter there is a rather wide range of choice. Perhaps 

 the very best sources of water supply are deep-seated and well-pro- 

 tected springs, lakes of considerable depth, or spring- fed brooks. 



In many instances spring water as it issues from the ground is 

 quite unsuited to fish-cultural purposes, and before introducing it 

 into the hatchery it should be exposed to the air for the correction of 

 possible faults in aeration. Sometimes it may be possible to excavate 

 a small, deep pool to form a reservoir, inclosing it to protect the 

 water from sunlight, leaves, and debris of various kinds and to pre- 

 vent small animals from entering it. Outside the spring house 

 should be a ditch deep enough to convey all surface water away from 

 the spring into a waste ditch. The inside of the reservoir should be 

 protected by a foundation wall of loose masonry, the point above 

 the water line being made substantial with mortar, building the 



