Placing Eggs In The Troughs

The eggs of a trout are about one-sixth of an inch in diameter, and nearly round. They are generally of a light straw or salmon color. The color varies with the meat of the fish. The redder the meat, the more orange colored are the eggs. They are generally of a light yellow or amber color at first, and grow darker as the egg grows older. Their specific gravity is a little greater than that of water, so that they will sink in water, but may be easily moved in it. Suppose the eggs to be obtained and that you have them in a shallow pan. The water in the troughs should be raised by placing a narrow strip across the trough upon one of the two inch strips dividing the nests. Then sink the pan gently to the edge in the water of the trough, at the same time tipping the pan, so that the water in the trough and in the pan shall come together with as little current as possible. Then the edge of the pan may be sunk into the water, and by tipping the pan a little more, the eggs will flow out without injury. By moving the pan while the eggs are running out, they may be spread uniformly over the bottom. If they fall in a heap, take the bearded end of a feather, and move the water with it in the direction you wish the eggs to go, and they will follow the current thus created. This may be done without touching the eggs with the feather. Distribute the eggs as evenly as possible over the surface of the nest. Where they are placed upon wire sieves, these may be moved and shaken under water so as to distribute the eggs evenly.

The strip which was placed across the trough to raise the water should then be removed. Care must be taken that it be not removed so suddenly as to cause a rush of water, which would carry most of the eggs away with it. Raise the strip a little way from the bottom so as to let the water run out gradually, and when it is very nearly or altogether at the proper level, the strip may be removed entirely. Those who have a nursery attached to the troughs place the earliest eggs in the lower end of the trough, and keep placing them toward the top, so that the fish which are first hatched can run first into the nursery without disturbing the others. We practice placing the eggs in the highest end of the trough first, because the eggs earliest placed, hatch out first, and the water should be raised over them, as they require more oxygen than the egg. If these first should be placed at the lower end of the trough, in order to do this the water must be raised over all the eggs; if at the upper end, strips can be placed upon the nests in succession as the eggs hatch out and the water left running upon the the un-hatched eggs as usual. About ten thousand may be placed in each nest eighteen inches by fifteen inches.

If the eggs have been received from a trout breeder, they should be left in the packages in which they have been sent until the troughs are ready for them. Persons will sometimes take the tin boxes containing the eggs out of the saw dust in which they were packed, and set them in the water of their troughs, with the idea perhaps of getting the eggs in the box to the same temperature as the water before unpacking them. This will surely kill the eggs in a few hours. Leave them in the original package until a few hours before you are ready to place them in the troughs. Then take out the tins and set them over or near the troughs, which will reduce or raise the temperature enough. Then empty the box into a tin pan full of water taken from the trough, pick out as much moss as you can readily with your fingers or nippers, and wash off the nest in the manner shown in directions for washing eggs hereafter.

If the eggs have had decent treatment on the way, that is not thrown about roughly or set near a red hot stove, you should find very few dead eggs in the boxes, not more than ten or twelve in one thousand. Should the eggs be found, on opening the box, run together in lumps instead of being evenly distributed, and turned to a dead white or milky color, it shows rough usage on the way.

Temperature Of Water And Time Of Incubation

The length of time required to hatch out the eggs depends upon the temperature of the water. A general rule sufficiently accurate for all practical purposes is this: At fifty degrees trout eggs will hatch out in fifty days, each degree colder takes five days longer, and each degree warmer five days less. The difference however increasing as the temperature falls, and deminishing as it rises. The best temperature for hatching is between thirty-five and forty-five degrees. We are inclined to be-lieve that the fish hatched at a temperature of about forty- five degrees and taking from seventy to seventy-five days to hatch, are stronger and longer lived, than those hatch-ed in fifty days at fifty degrees. It may be well, also, to note that the eggs earliest taken produce the best fish. The water of a spring can be reduced in temperature in winter by letting it run for a short distance exposed to the open air, or it may be collected in a pond and the supply either drawn from the pond or the stream whichever is regarded as the most desirable. An-other reason for delaying the hatching of trout is to bring them well into spring before they are turned louse, as at that time they can get more abundant food than they could earlier.

Growth In The Ego

A great mistake is often made where eggs are to be distributed in retaining them too long after impregnation. This is sometimes done for convenience in shipping, and sometimes with a view of shortening the operation of hatching in the hands of the person receiving them, but it is all wrong.

About the twentieth day, the young fish can be plainly observed in the egg. Put a few eggs in a small phial and with a magnifying glass the formation of the fish can be easily seen. Fish farmers should send the eggs away at this time. Some of the eggs are not impregnated and at this stage of growth may easily be distinguished from the others. The dead eggs will turn to a milk or a pearl white color, and should be removed with the nippers as fast as they are discovered. If left in the trough a fungus growth forms upon them which extends to the other eggs in the immediate vicinity and kills them. Care should be taken in using nippers, not to hurt the other eggs, and to do this the bad egg should be feathered entirely separate from the rest; a very slight blow or jam from the nippers will be sufficient to destroy their vitality. Rats and mice in the hatching house often destroy many eggs; they are very fond of them, and going into the troughs to get them will destroy with their feet many more than they eat. A wire screen, or boards laid over the troughs will keep them out, but it is a much cheaper way and just as effectual, to keep them down by traps or poison. The eggs should be feathered over occasionally so that their whole surface may be exposed to the action of the water.