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The Culture of Fish

Pisciculture Is the name of a new and very important art destined, we believe, ere long, to hold a conspicuous place in human interests and pursuits. The extent to which Nature may be aided by artificial methods in the breeding of fishes, is a truly wonderful discovery. That eventually, and at no distant day, it will become the means of adding largely not only to the quantity but the variety also of those supplies for man's sustenance and luxury, admits scarcely of a doubt.

Fishes, whether in the freedom of nature or in artificial receptacles, show plainly enough the approach of spawning. The belly of the female becomes distended and yields readily to pressure.

There is a fluctuation under the hand, which shows that the eggs are free from the ovary and easily displaced. This being the case, take up in your left hand a female fish, and hold it suspended by the head and thorax over a flat-bottomed vessel containing clear water. Then with the right hand passed from above downwards, squeeze the loosened eggs through the anal opening. A male fish is then taken, and the milt is expressed in the same way, though often it flows by the mere act of suspending. This substance, white and cream-like, soon gives to the water the appearance of whey. To insure effectual fecundation, 080 8000006 The subsequent processes may be carried on upon the spot, or the impregnated eggs may, like those of the silk-worm, be packed and transported to other places, there to be hatched.

In the first case, the water with the eggs in it is poured immediately into the hatching apparatus. This may be very simple. Mr. Coste tells us that he has often used a long and narrow wooden box lined with zinc or lead, with a fish-box of earthenware. In the laboratory of the colleges of France, the troughs used are of potter's enamelled ware. The eggs are spread upon a movable frame or grate composed of glass rods, about one-tenth of an inch apart. It seems to be a condition of Nature that this operation of hers, like the great water lily of the tropics, can go on well only in running-water. The water which supplies the hatching-trough must have a constant flow. Double sieves of wire gauze set in floating frames, which keep them immersed, but near the surface, have been used for hatching fish in ponds and rivers; but the mud is apt to gather in them, incrusting the eggs and making it necessary to remove them for the purpose of cleaning. Such changes retard the process of incubation. Even after they are hatched, the young fish are apt to chafe the umbilical vesicle by coming in contact with the wire, an injury which generally proves fatal.

In preference to the above M. Coste recommends the use of a wooden box with hinged ends and cover, in all of which are openings for the water, protected by wire gauze, and containing also a fourfold frame of glass rods for the accommodation of the spawn. In the course of a few hours after the process of fecundation, a change may be seen in the eggs.

At first they become opaque, but soon resume their transparency. A small, round spot next appears, which gradually extends until one end takes the shape of a tail, and the other that of a spatulashaped head. Two black points upon the sides presently turn into eyes. It is not long before the young animal gives sign of life by motion of