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CHAPTER II

REARING

WATER AND HATCHING-HOUSE

A SUITABLE water supply may be described as the first requisite of trout culture. Nothing can be done without this. On it everything depends. To secure a flow of suitable water must, therefore, be your first concern. Water taken from a brook or river is the best for rearing the fish, but for hatching the eggs use spring water if possible. A spot which yields both spring water and brook water gives you a great advantage. It need hardly be said that the water must, in either case, be free from all suspicion of pollution. Iron, lime, or sulphur, if present in great excess, unfits the water for trout breeding in any stage, but occasional muddiness is not a disadvantage in brook water for rearing the fish after the hatching period has passed.

Having found water suitable in quantity and purity, there still remains the vital question of supply.

Is it ample, and will it continue ample always, day and night? Will the flow of water, like Tennyson's Brook, 'go on for ever'?

In this respect it should be able to stand the severest test ; even after prolonged drought the stream must still continue to flow in plenty. If it will do this, well and good; if not, then look elsewhere for your water supply.

But this is not all. The opposite extreme must be guarded against. It is not of course a disadvantage to have a greater supply of water than you require to take, but there must be no risk whatever of flooding; the situation must be one in which you will under no circumstances lose the power of control and regulate your flow of water as you may think fit. Nor must the water be liable to become overheated in the summer through exposure to the sun. Beware of water, the temperature of which is liable to rise above 70 degrees Fahrenheit. If you limit your operations to hatching a small number of eggs and rearing a correspondingly small number of fry, all this can, with suitable apparatus, be accomplished readily by means of the ordinary domestic water supply of a town or country house.

I recommend you to protect your spring or supplycistern with a closely fitting cover to exclude animals,

leaves and dirt, and to screen the water from the sun's rays.

Having secured a plentiful and unfailing supply of clean, cool water, beyond the reach of floods, your first difficulty is overcome. The next thing is to provide yourself with the necessary apparatus for hatching the eggs, and rearing the young fish.

Do not attempt to conduct your hatching operations in boxes placed out in the open air. From cold there is little to fear for eggs or the fry, but unevenness of temperature is very undesirable, and all risk of accidental disturbance has to be securely guarded against. Moreover the operator himself will require shelter during the hatching season, which occupies the winter months. A house or shed therefore of some kind should be brought into requisition.

Almost any kind of weather-proof structure can be made to answer your purpose, but a conservatory or greenhouse is not generally a suitable place for hatching and rearing operations, which require an even temperature. A hatching-room need not be an elaborate or expensive erection; it should be easy of access from your house, and not far from the source from which your supply is taken.

The glare of the sun's rays is very injurious to the

eggs and also to the newly hatched fish. A dim light suits them best. The interior of the hatching-house should therefore in the daytime be shrouded in twilight. But you cannot work in the dark; light therefore should be admitted as and when you require it through windows or skylights screened by movable blinds. These blinds should be kept closely drawn, especially on the south side, at all times except when you are actually at work.

The exclusion of the sun's rays helps to keep the temperature even, and to prevent the growth of a fungus which strong light has a tendency to foster. But there are worse enemies than the sun's rays to be shut out. Rats, mice, weasels, birds, &c., prowl and hover around bent on plunder; therefore have a wellfitting door, and let this door be provided with lock and key, and on no account allow visitors to enter unattended. Smoking in your hatchery should be 'strictly prohibited.'

To secure the necessary fall the house should be so arranged or situated that the water may enter the room several feet above the floor. For this purpose the soil can, if necessary, be excavated, and the floor sunk to the required level; or the building can be erected on lower ground. This will enable the hatching-boxes to be raised to such a height as to be

convenient for you to examine the eggs without much stooping.

The supply-pipe leading the water into the hatchery should be protected against frost. In the case of a spring this may be done by laying the pipes underground. The receiving end of the pipe should be covered with a cap of perforated zinc, to prevent the possibility of any object alive or dead causing an obstruction.

It is necessary that the water which passes over the eggs should be clear and, as far as possible, free from sediment which is injurious to the eggs. Good spring water requires very little filtration, but if you are dependent on a brook or river for your supply, the water will have to be made to pass through a filter before it enters the hatching-boxes; and if the stream is very muddy you will have to adopt the further precaution of allowing the water to clear itself in a settlingtank.

Before entering the hatching-boxes the water should be exposed to the air. This is specially desirable where your supply comes straight from a covered spring, and the water first sees daylight in the hatching-boxes. The water is therefore passed into a long open trough or tank placed across the upper end of the hatching-boxes, and as high above them as