Hidden Water Sources for Trout

that in addition to the visible water supply running into a pond there are springs in the pond itself, or there is a considerable quantity of water percolating through the soil, and this alone is a very valuable help to its trout producing capacities. In the deeper pond there is a greater probability of such an additional supply. I have known ponds which have thus been fed by copious springs, but which have possessed no visible water supply, that is to say, there was no stream running into them, and yet they have proved capable of maintaining a nice head of trout. Sometimes we find a pond from which there is a considerable overflow, but no stream apparently feeding it. In such a case there must be springs, and such a pond may do for trout. Occasionally in ponds of this nature, however, the water How to obtain it. 61 is too cold or barren, and will not grow trout at all, whereas, the same water supplying a second pond will do very well for the purpose. The fact is, that it simply requires a little cultivation to render it fit for use. After being exposed to the air and the rays of the sun in the spring pond, which contains also some vegetable life, it becomes changed in its nature, and in passing out of this pond and along a raceway, even though the latter be only a few yards in length, it becomes still further changed. This applies more or less to a great many springs. The water often becomes so rapidly changed that trout will thrive even in a spring pond. I have had cases in which they have done well in ponds that had neither visible inlet nor overflow. Being fed by springs the water would rise to a certain level, when, owing to the nature of the soil, the absorption was so great that it could rise no higher. There was, in fact, a stream flowing through the pond, and a pond of this nature may be an excellent place for trout. Water readily takes up oxygen, and the more rapidly this combination is brought about the sooner does it become suitable for maintaining them. Whilst receiving a supply of oxygen it also precipitates substances held in solution, and thus it will be seen that the water flowing out of a pond may essentially differ from the water flowing into it, if it be from springs. Plants give off oxygen, and, as a rule, in other ways tend to render it more suitable for fish. It is a well-known fact that even impure water' as in the case of a stream, becomes purified as it pursues its) course. Exposure to the air and the absorbing power of the earth and other causes are at work to bring about this change. Where the water supply is obtained from springs, therefore, it is desirable to pass it through a preparatory pond if practicable, and I it is important that this pond should contain vegetation of a proper kind, as the plants not only give off oxygen but produce favourable conditions for a crop of natural fish food. So much, then, for ponds with a limited water supply. Where a good supply is at hand I would say secure it by all A means. stream that will fill a twelve-inch pipe will keep a I good series of trout ponds going. If double the supply can be | obtained at times so much the better. Although it is not only desirable, but necessary, in the case of a successful trout pond, .to 62 How to obtain it. regulate the water, yet the supply should not always be just the same. It is not so in nature. There are freshests or spates which are often very beneficial to the fish. Now, we have the advantage | in a well ordered fish pond of producing these artificially, whenever desirable, and what is more, we can have the spate without a flood and without fear of an overflow. Anyone who has seen an artificial spate sent through a pond during dry hot weather in July, would never doubt again the beneficial influence it had on We the trout. know that in streams they often suffer very much during droughts, and occasionally even die in numbers. What a great advantage it would be in such a case to send down an artificial spate occasionally, giving the fish not only additional water, but taking care that that water was charged with trout food. It could easily be done and would be an invaluable help, and I venture to say it will be done before long. I shall never forget a case in which I was once called suddenly in the month of July, to look at some trout in a pond that had been almost deprived of its water supply during a long drought. When I arrived I found but a mere trickle going into the pond, where the sun's rays had heated it to a dangerous degree. Not a drop was running out, and the water had fallen considerably below the overflow level, owing to the loss by evaporation and soakage. The trout were gasping on the surface, and a crowd of them also in the same condition were about the inlet. The case looked hopeless, but nil desperandum. The pond was supplied from a mountain stream, and this stream, like hundreds of its class, was almost dry. But it consisted, as most mountain streams do, of pool after pool, and some of them were of fair size. Obtaining a couple of men armed with crowbars, spades, and pickaxes, I had them at work in a few minutes letting off these natural water supplies. There was no difficulty about it, as the stream bed consisted mainly of boulders and gravel, and by shovelling away a little of the latter or lifting a boulder or two a considerable amount of water was liberated, and in a few minutes a small artificial spate was going merrily through the pond. The fish revived at once, and thus a valuable stock was saved from certain destruction. Had this not been done, at least three-fourths of them, if not all, would have been dead in a few How to obtain it. 63 hours. As soon as the water in the pond had become thoroughly changed I allowed the stream to slacken considerably, and during the night it only ran as I had at first found it. The fish had recovered, and water was valuable, as we did not know for how many days the drought might continue. Next day, however, the operation of letting off more pools was continued, although with great care, no more water being sent down than was absolutely needful to keep the fish in a fairly good condition. This operation was continued for five days more, when a friendly thunderstorm drenched the hills and sent down a copious supply, which did not fail again that summer. Before the next a supply had been obtained from another and larger stream. In the instance I have just narrated the fish were not only benefited, but their lives were actually saved, by an artificial spate, and the great benefit arising therefrom will be plainly perceptible. So at any time during dry weather, although there ] may be no danger whatever existing, an artificial spate sent] through a pond is an exceedingly good thing for the fish. It may be produced by contrivances of the roughest and simplest A kind. few small dams should be made, not across the stream itself, but in any suitable corners close to it, where a trickle of water is obtainable to fill them. This means that there will be practically hardly any stream going through them, and thus they become excellent places for growing a crop of trout food, which, of course, goes down with the water into the fish ponds when the dams are let off. And here it should be observed that these dams should never be run dry. By only running half the water off, or at most three-fourths, a sufficient stock of living food is retained in them to keep up the required supply. Having made secure the point at which the water enters the pond, the next thing is to provide for its escape when the pond is full. There are many methods by which this may be effected. One that I have found to be in very general use, is to allow it to take the shortest possible cut over the embankment, in a channel the bed and sides of which are more or less paved. They may, of course, be built of solid masonry. So far good ; but there are many things to consider, which I find in most cases have not been thought of at all. Should the pond be in an exposed situa- 64 How to obtain it. tion, it is often desirable to make the outlet as near the south-west corner as practicable. Our prevailing wind being south-west, and most of our heavy gales coming from that quarter, it will be apparent that the effects of the wind will be to keep the south- west corner clear of floating matter. When the outlet is in the opposite corner, all the floating matter is driven right on to the screen, and causes much extra trouble. In some cases the situation of the outlet in a rather bad position as regards the wind is almost unadvoidable, but in a great many instances it is quite a simple matter to arrange it on either the southern or western side of a pond. Of course some pools are sheltered on the south-west, and exposed to east winds, and work best with the outlet on the east side. It is therefore necessary to take the bearings and study the peculiar circumstances surrounding each case, and then decide on the best place in which to construct an outlet. The result may perhaps be that the best position for it, as regards wind, may prove to be on the same side or very near the place at which the water enters. This, again, is not good, and it may be desirable to convey it, by means of a raceway, round to the opposite side, and turn it in there, so as to make sure that it runs completely through the pond. This may often be easily done, and is an advantage, inasmuch as it provides an extra length of spawning ground for the fish. Or it may be done by placing the leaf screen half-way DD along the raceway (see Fig. i) instead of at the point C. or D. So much, then, for the position of the outlet. Here let me say that the east wind is sometimes as bad for fish as it is for man and beast. It has been found that under some circumstances fish are adversely affected by it. This is one of the many points that require investigating, and every scrap of information that can be gathered together will tend to teach us something more about that of which we know comparatively little We at present. do know that in^ laying out fish ponds for profit, which are necessarily small and heavily stocked with fish, the east wind is a factor which has not to be overlooked. Having considered the position of the outlet, we have now to decide which is the best plan to make one one that can be relied upon to work in all weathers, with the least possible attention or care on the part of the attendant. That care must be given to an How to obtain it. 65 outlet screen goes without saying. It should be the duty of some one to attend to it as often as may be required. The amount of attention needful varies very much indeed in different cases. I have screens working which are not touched oftener than once in three or four weeks, and I have others that require attention every day and sometimes twice daily. There are exceptional times, that come perhaps once a year, when a screen requires special attention for a few days, as, for instance, during a slight rise in the water in autumn when the leaves are falling. As I have already pointed out, a good deal depends upon the position of a screen, and much also upon the way in which it is guarded. I have seen one that was almost hopelessly unworkable work quite easily after steps had been taken for preventing the floating matter from coming on A to it, and this can often be done in a very simple manner. few bundles of sticks or of thorns placed in the water so as to form a semicircle just above the screen have done excellent service many A a time. wooden hack placed two or three feet in front of it will answer the same purpose. I have seen wire netting used, but it has the objection of being bad to clean. From a wooden hack, or an iron one either, rubbish can easily be raked, but not so easily from wire netting. Should it be the most convenient device at hand, it should be stretched upon movable frames that can be lifted bodily and well shaken, or the netting beaten with sticks or switches to clear it of the mass of material that is at times sure to collect upon it. Bundles of thorns, hedge clippings in fact, do very well, and if plenty of them are used they are most efficacious. The working of a screen may also be materially helped by planting a bed of reeds (Arundo phragmitis) or of bullrushes (Typha laiifolia) in front of it. These will do excellent service in keeping it clear, by preventing the bulk of the floating matter from reaching it at all, and by working a few bundles of sticks at the back of a reed bed a screen may be made to give very little trouble indeed. "Where there is a will there is a way," but the disgraceful manner in which many of the outlet screens I have seen have been worked would lead one to suppose that it was a very difficult way. On newly-made fish ponds, however, it should I not be so. F 66 How to obtain it. The next question is What is the best kind of screen? There are several important points to notice. A (1) screen should fit well into its place. (2) It should be strong. (3) It should be well let into the bank at each side, and especially underneath, so that the water cannot by any means flow round it or underneath it. (4) It should be large enough. (5) It should be so constructed that it will not allow any fish to escape. Only on very rare occasions have I come across screens that possessed all these qualifications. In travelling about the country inspecting ponds and lakes, I have not found one piece of water in fifty to be possessed of such a screen. Many have been introduced at my suggestion, and have worked most successfully. The proper working of a screen depends largely upon the man in charge of it. Occasionally, one meets with an individual whose .mind is made up before he sees it or begins to attend to it, and in such hands it has usually a poor chance. I have seen one that would not work at all under the care of one man do its work admirably when in charge of his successor. There are several different forms of screen which we will consider by and by. Before doing this, however, let us turn our thoughts to the material of which they are to be made. I have at i present close upon a hundred screens working about my ponds, I and I have always used perforated zinc, and have found it to work well. If is fitted on to wooden frames, and these being all of the same size, one can be withdrawn, and another of coarser or finer perforation be readily put in its place. This on a fish farm is very necessary, as large fish may be taken from a pond and replaced by small ones needing a finer screen. Perforated zinc works well, is not expensive, and is easily manipulated by any one who can use a hammer and nails. Should a hole get punched in it by accident, it is easily repaired by lacing another piece over the hole with the help of a little brass or copper wire. Ordinary zinc requires renewing about once a year, and this is its only drawback, but to set against it is the advantage it possesses in being so easily put on. It can be obtained of considerable thickness, however, and How to obtain it. 67 then lasts much longer. Perforated iron plates do very well, and are of course more permanent. They require no frames, and are An quite easily fixed. ordinary iron grating is also excellent, but it must be borne in mind that a fish can readily pass between two bars of metal which could not possibly pass through a round hole of the same diameter. The bars may be a quarter of an inch or they may be half an inch apart, but the greater the width between them the more readily will fish pass through and escape. It may be argued that fish do not go down stream out of ponds. ^ I know many ponds where there is no outlet screen, and where it has been supposed there is no need for one. This is a mistake, however, and I have met with instances in which fish have been lost in considerable numbers owing to it. At times, and under certain circumstances, they will and do go down stream if not prevented. There are some instances, however, in which a large number of fish may run up stream into a pond, and of course all things have to be taken into account, and each particular case treated according to circumstances. One thing I am quite sure of, and that is, that every fish pond that has been specially made and stocked with fish, and that has a regulated supply of water, ought to have an outlet screen. Having decided upon the material that is to be used, the next thing is to consider the more important points that are to be We observed in the fixing of a screen. must first be sure that it | is capable of passing all the water during rainy weather. This is in itself a very simple consideration, and in the case of a well made pond that is not subject to flooding, is easily calculated. By having a screen that will pass double the quantity of water that can by any possibility flow from the pond, it should be fairly safe. Of course, the amount of floating matter that is liable to be driven on to it must be well considered and allowed for, and it is better to have the screen twice as large as is necessary than to ^ have it just a little too small. One double the capacity required is usually large enough for all emergencies. There are so many old ponds in use that are liable to have floods tearing through them, that I will just give a hint or two concerning them. The chief point in their case is to have the screen large enough. Make it as big as you like, but do not on 68 How to obtain it. any account have it too small. It will do no harm by being made too big, and will give less trouble. Where the size can be given in width and depth the matter is simple, but sometimes this is not convenient. There may be an opening through which the water passes that cannot be easily altered, and which at the same time is too narrow for a screen to work. In such a case the screen must project into the pond, and may be on the rectangular system that is, consisting of two sides and a front or it may be made semi-circular, and in this case may be much wider than the outlet. In cases where there is much floating matter and heavy flooding, it may be commenced several yards from the outlet, beginning on the pond bank, and running out in semi-circular form until it reaches the bank again, a few yards on the other side of the outlet. It will be apparent that the greater the dimensions of the screen the less will be the liability to become choked, and, consequently, the more easily will it be kept in working order. It is very desirable that a screen should be well fixed, that is, that it should be so let into the banks of the pond that there is no chance of the water flowing round it, or under it, instead of through it. This end can be attained by means of masonry or concrete, in which the screen may work, and which must be well A puddled behind. very simple and effective way of fixing a screen, when made of wood and perforated or woven metal, and one which I have frequently followed, is explained by the annexed diagram : Fig. 2. How to obtain it. -;, v . 69. A B is a bar of wood, underneath which is the wire or perforated screen, as shewn. On the outer ends of this bar, where it extends to C and D, are nailed several boards. Another cross bar lies at the back of the boards just below the screen, e to f, and another at the bottom of all, g to h. The whole of the wood- work below the dotted line k, /, m, n, o is to be buried in the bottom and banks of the raceway, and, in constructing it, the screen should be made of a suitable size to fit the raceway, unless it be intended to use a projecting one. In such a case A no screen is fitted into the opening below B, but the projecting one may be fixed to the woodwork, and instead of working in the raceway it works in the pond. There is a great advantage in using wood, inasmuch as joints, alterations, and repairs are easily made. It is true that it is more liable to decay than stone, but it lasts a long time, and is not so often damaged by frost, and it has the advantage of being less expensive and more easily adapted than masonry. It should always be charred, both for the sake of \ preservation, and to prevent the growth of fungus ( Saprolegnia). \ A screen constructed in this way will be found a very simple affair, and the filling of the trench which has been dug to receive it, if properly done, will render it perfectly tight and secure. If the work be done in concrete or masonry the principle is still the same, and will ensure safety unless it has been very clumsily managed indeed. The screen can be made to slide in a groove or be a fixture, as may be most desired. There is not much fear of the water getting round or under- neath such a screen, and it will be found to be worth the labour expended upon it. Fully three-fourths of those I have come across which have been made in some other way have been found to be useless. Once I was called to inspect a small lake that had been stocked by an enterprising hotel proprietor. The fishing had not improved as it should have done. We made a careful survey of the