Supply Of Water For Given Number Of Trout

This has never been accurately determined, and we do not know that any general rule can be given applicable to all times and places. The quantity required for any given number depends very much upon the temperature of the water, - a certain supply in cold weather sustaining many more in good condition than the same supply in hot weather. It is the same with trout as with mankind. If many people are packed together in a close room, they will soon begin to suffer; but will not feel the bad effects so soon in cold weather as in warm. Now the water contains the air upon which the trout lives, and the amount requisite depends upon the amount of air which is in the water. A still and smoothly flowing stream, with little vegetation in it, contains the least amount of air. Hence the value of a fall of water between the ponds if the stream is small. The volume of water required depends also upon the shape of the ponds and upon the size of the fish. We can only say about what quantity is necessary and leave each owner of ponds to observe for himself whether more or less fish do well with it.

It must always be borne in mind that the larger the supply of water the better for the trout; and the trout-breeder on a large scale will find better success with small ponds and large supply than in any other way. For ten thousand fish the stream should not be less than seven inches square (that is, forty-nine square inches) and would be still better if it was seventy-five square inches. A less supply will perhaps do; but with it there is danger of disease and death to the fish. We will say then a supply of water filling a pipe five inches square (making twenty-five square inches) for the size of ponds shown in plate on a previous page calculated to sustain five thousand fish in the second, and two thousand fish in the third ponds. The first pond to receive six or eight thousand young fish, need not have more than two or three square inches of the water. This estimate of number of fish is purposely made low. More fish may be able to live with the supply mentioned; but the number given certainly can.

Growth Of Trout

It is impossible to tell the age of a trout by its size, as its size depends very much upon the quantity of food which it obtains. It is a general rule that with good feeding a trout three years old will weigh one pound. They have been known to live for years at the bottom of a well, where the supply of food must have been extremely limited, and remain through all those years, apparently at the same size. Then again, with good feeding, they will more than double their weight in a single season. Trout will not grow so fast in swift running water as in a pond The largest trout are never caught in narrow parts of the stream where the water runs fast. But where the stream swells out into a dark and still pool, there the patriarchs are found. We presume that the largest trout now taken in this country are found in the lakes of Maine. Some will grow much faster than others under any circumstances. A few will always look lean and hungry no matter how much they are fed, and others seem to have a peculiar knack of getting fat. Still the rule of good feeding applies equally to all. They will not grow so fast when three or four years old as before; that is, the rate of increase diminishes with age. The average age of trout is perhaps twelve or fourteen years. On this point we cannot speak with certainty. We have seen trout grown from the egg and kept in confinement and well fed on beef lights and hearts that weighed in the spring after the year they were born, or say when not over fifteen months old, as much as three quarters of a pound in some instances, and all averaging a half pound apiece. Judging from those in our possession, we suppose a trout to be in its prime when it is from three to ten years old. The size is largely a question of food. On Long Island where they have access to the salt water and teed on the numberless small fish and Crustacea abounding in the sea, the trout are notoriously large, while in the mountain streams, where the food is scarce and precarious, it is just as well known that the trout are small.

The size to which a trout may grow is not very well settled; so many "fish stories" have been told that discredit is thrown even upon well authenticated assertions. Trout may in exceptional cases and in large waters attain the weight of eight or ten pounds, but a four pound trout is generally considered to be of pretty good size. This question of size is interesting rather to the sportsman that to the trout farmer. It is considered that small trout are the best to eat, those from one-quarter to one-half a pound. A better market may always be found for fish of this size than for any other. There is only one market in the United States where there is a demand for very large trout, and that is New York, where the largest trout sell the most readily. Besides, fish of small size are the handiest to manage on the spawning bed, and more of them can be raised. If the spawn is extracted by hand, the difficulty in handling a two pound trout is very great and increases very fast as the fish grows larger. Not only is it troublesome to handle the large ones, but the danger of killing them is much greater; so that, in our opinion, from one quarter to one pound weight is as large as the fish farmer should attempt to grow his trout, unless from motives of curiosity to see how large they will get to be.

As to the growth of salmon, we can say that in confinement in small stew ponds the California salmon will attain about the weight of three-quarters of a pound, and the Kennebec or Eastern salmon a little more. None of the California salmon had, when this was written, produced eggs while retained in the fresh water, but the milt is developed and has been used for fecundating trout and salmon trout eggs. When at liberty and allowed to visit the ocean, salmon grow much faster, and we take the following extract from the report of Maine Commissioners of Fisheries: Salmon. In our issue of May 3d, we made mention of a very large salmon caught at Cape Jellison, Stockton, by Josiah Parsons, and purchased by Frank Col lins, of this city. The fish measured fifty inches in length and weighed thirty-three and a half pounds. Attached to the fish was a metallic tag numbered "1019," indicating that it was one liberated from the Bucksport Breeding Works. The tag was forwarded to Mr. Atkins, the superintendent of the works, who keeps a record of all fish used for spawing purposes and liberated. We now chronicle the record of the fish, as learned from a letter from Mr. Atkins to Mr. Collins, He writes that the salmon was liberated at Bucksport, Nov. 10, 1875. It was a female fish, thirty-nine and a half inches in length and yielded five pounds and six ounces of spawn, or about 16,000 eggs. After spawning, it weighed sixteen pounds He judges that in the preceding May, (1875) the fish weighed twenty-five pounds. Thus the fish in two years had grown nearly an additional foot in length and eight and a half pounds in weight. One important fact in the habits of the salmon has been demonstrated by the use of these tags, and that is, that the fish, after it becomes large, does not visit the river every year, as was formerly supposed, but only every second year. Those liberated in the Penobscot in 1873, were recaptured in 1875, and those let loose in 1875 are now being caught. One dollar premium is paid for every tag thus found. The Penobscot river about Bangor is reported to be full of young salmon."

But it is very probable that both California and Penobscot salmon will spawn in fresh water if they have fair range, that is to say, a pond of good size. In Iowa, see Report of '75-7, p. 12, the Eastern salmon when in a pond, were said to have grown in two years and a half to weigh from two and a half to seven pounds; if this is so, and these were not salmon trout, there is no reason the California salmon should not grow as large, or nearly so.