Amateur Fish Culture.

by Charles Edward Walker.

PREFACE

My aim, in this little book, has been to give information and hints which will prove useful to the amateur. Some of the plans and apparatus suggested would not be suitable for fish culture on a large scale, but my object has been to confine myself entirely to operations on a small scale. I have to thank the Editor of _Land and Water_ for permission to publish in book form what first appeared as a series of articles.

CHARLES WALKER.

Mayfield, Suss.e.x.

_March, 1901._

CHAPTER I

INTRODUCTORY

Fish culture of a certain kind dates from very early times, but its scientific development has only come about quite recently. Most people know that in our own country the monks had stew ponds, where they kept fish, princ.i.p.ally carp, and also that the Romans kept fish in ponds. In the latter case we hear more often of the eel than of other fish. The breeding of trout and salmon, and the artificial sp.a.w.ning and hatching of ova, are, however, an innovation of our own time.

Much has been discovered about the procreation of fish, and in no case have scientists worked so hard and discovered more than in the case of _Salmonidae_. Fish culture, particularly trout culture, has become a trade, and a paying one. To any one who has the least idea of the difficulties to be overcome in rearing _Salmonidae_, this fact alone proves that fish culture must have progressed to a very advanced stage as a science.

This advance has in very many, if not in the majority of cases, been made by the bitter experience gained through failures and mishaps, for these have led fish culturists to try many different means to prevent mischances, or to rectify them if they have happened. Some of the most serious difficulties experienced by the early fish culturists who bred _Salmonidae_ can now be almost disregarded, for they hardly exist for the modern fish culturist, with the knowledge he possesses of the experience of others.

So much of what has been done in fish culture is generally known to those who have studied and practised it, that the beginner can nowadays commence far ahead of the point whence the first fish culturists started. Many of his difficulties have been overcome for him already, and though he will not, of course, meet with the success of the man of experience, still he ought with the exercise of an average amount of intelligence to avoid such failures as would completely disgust him.

There are many pieces of water containing nothing but coa.r.s.e fish which are very suitable for trout of some kind. Ponds, particularly those which have a stream running through them, will, as a rule, support a good head of trout if properly managed. Again a water which contains trout may become more or less depleted, and here it is necessary to supply the deficiency of trout by some means. The easiest way is, of course, to buy yearling or two-year-old fish from a piscicultural establishment, of which there are many in the kingdom, but I know that there are many fishermen who would much prefer to rear their own fish from the ova, than to buy ready-made fish. Any one who has the time and opportunity to rear his own fish will be amply repaid by the amus.e.m.e.nt and interest gained, and it should be the cheaper method of stocking or re-stocking a water.

The same remarks apply to a certain extent to waters which will not support trout, or where the owner wants more coa.r.s.e fish. The stock of coa.r.s.e fish may be improved by fish culture just as much as a stock of trout.

In his first year or two, it is very possible that the amateur will not save very much by being his own pisciculturist. If, however, he is careful, and works with intelligence, it is quite possible that he may succeed better than he had hoped and rear a good head of fish at a less cost than the purchase of yearlings. In any case he will have had a great deal of pleasure and gained experience as well as reared some fish.

In the present little volume, I propose to try and deal with fish culture in such a way as to help the amateur who wishes to rear fish to stock his own water. Much of the existing literature of the subject deals with it on such a large scale that the amateur is frightened to attempt what is apparently so huge an undertaking. Fish culture may, however, be carried out on a small scale with success, and though considerable attention is necessary, particularly with young _Salmonidae_, it is not a task which involves a very great proportion of the time of any one undertaking it. It is absolutely necessary, however, that the amateur fish culturist should live on the spot, or have some one who is intelligent and perfectly trustworthy who does. In every case in my experience, trusting the care of young fish to a keeper or servant has resulted in failure, and in every failure I have seen where the fish have not been trusted to the care of a servant, the cause has been very obvious, and could easily have been avoided.

The rearing of trout is the most important branch of fish culture to the amateur, and fortunately but slight modifications are necessary in rearing other fish. What is good enough for trout is good enough for most fish, therefore I think that I shall be right in describing trout culture at considerable length, and dealing with other fish in a somewhat summary manner. The difference in the management, etc., of other fish I shall point out after describing how to rear trout.

To begin with, the amateur must not suppose that because he puts fish into a stream or pond he will succeed in stocking that water or increasing the head of fish. There are many other things to be considered. The river, stream, or pond must be of a suitable character for the fish, and there must be plenty of food. I am sure that it is much more important to consider carefully whether the water is suitable, and contains a proper supply of food, than to consider how the fish are to be obtained, for recourse may always be had to a professional fish culturist--fish of almost any kind and any age can be bought ready made.

The point I would impress upon the amateur more forcibly than anything else, is that he should be sure that there is plenty for his fish to eat in the water, before he thinks of putting them into it. It is for this reason that I devote my next chapter chiefly to the stocking of waters with food and to the improvement of the food supply in waters where some food already exists.

CHAPTER II

STOCKING WATERS WITH FOOD

It may seem somewhat superfluous to say that fish cannot live in any water unless that water contains the food supply necessary for them to thrive upon, and yet this is the point most often overlooked in stocking waters with fish. Small attempts at stocking with creatures suitable for food, particularly after the fish have been already introduced, are not at all likely to succeed. Such an important matter when treated as a small afterthought is almost sure to end in failure of the whole business of stocking.

But a small amount of thought will convince any one that in order that there may be a sufficient amount of animal life in a water, there must be an adequate vegetable life, for weeds are almost always necessary to the well-being of the creatures which serve as food for fishes.

In the case of a pond it is generally fairly easy to introduce a good stock of suitable weeds. The best method is to let the pond down as low as possible, and then to plant some weeds round the margin; the water is then allowed to gradually fill up the pond, and as it rises weeds are planted round the rising margin of the water. In ponds which cannot be emptied at all, or not sufficiently to carry out this plan, weeds may be planted in an easy but not quite so effectual a manner. They may be planted in shallow baskets containing some mud from the bottom of the pond, and then lowered in suitable places from a boat, or bundles of the weed may be tied to stones and dropped into the water in a similar manner.

These latter methods are, of course, not so good as actually planting the weeds round the advancing margin of the water, for success depends to a certain extent upon chance. Some of the weeds thus planted are, however, sure to take root and grow. Plants of different kinds, of course, are necessary at different depths and on different kinds of bottoms, and good kinds are necessary at the margin of the water as well. I give a list of some suitable plants of each kind at the end of this chapter.

Similar methods are used in planting weeds in rivers and streams to those used in ponds. If the weeds are planted in baskets, the baskets must, of course, be weighted when put in a position where the current can act upon them.

Besides vegetation in the water, vegetation on the bank is of considerable importance. I shall deal with this at a later period more fully, as trees and bushes, besides harbouring many insects which serve as food for fish, have also considerable importance in giving cover to the fish and to the fisherman who is pursuing them.

I think that in the case of a bare water, a year at least should be devoted to developing a good supply of vegetation. This will generally produce a considerable amount of animal life, without any artificial help, but judicious help will be sure to accelerate matters to a considerable extent. I would, however, advise the amateur not to attempt to introduce a quant.i.ty of creatures into his water, until the vegetable life therein is well established. For instance, though fresh-water snails are desirable in every trout water, if introduced in large numbers into a water in which the vegetation is small and not well established, they will eat down the weeds too much and then die off from disease caused by want of sufficient nourishment.

Having established the vegetable life well in a water, and developed it to a considerable extent, the amateur may begin to examine his water, and find out how much animal life exists there, and to stock with creatures suitable for food, according to what he finds in the water.

Fresh-water snails are always desirable. In streams, or in ponds with streams running into them, the fresh-water shrimps (_Gammarus pulex_) should always be tried. It does not do in some waters, but where it does thrive it increases very rapidly, and forms about the best article of food that can be given to trout. _Corixae_, which thrive in ponds and sluggish waters, should always be introduced. They increase rapidly, and are taken by most fish, particularly by trout. The amateur should be careful when he introduces these creatures to make sure that he is putting in the right creature. The water-boatman (_Nautonecta glauca_) is a member of the same family, but is no use as food for the fish. He swims on his back, is longer and narrower than are _Corixae_, which do not swim on their backs, are smaller, broader, and live much more under water than the water-boatman. It is generally advisable to avoid water-beetles, as most of them are more likely to do harm than good, such a number of our water-beetles being carnivorous. They will probably not harm adult fish, but they will destroy ova and fry. I have known a _Dytiscus marginalis_ kill a trout of nearly a quarter of a pound in weight.

In order to make sure of not introducing carnivorous water-beetles into a water, I think it best as a rule not to introduce beetles at all.

_Corixae_ are, however, so like beetles, that many people call them beetles, and therefore I will give a few points which will make them easily distinguishable from each other. In beetles, the wing-cases (elytra) meet exactly in the middle line, in _Corixae_ and other water-bugs, the anterior wings, which resemble the elytra of beetles, overlap, which causes the line on the back to curve away to one side at the lower end. In beetles the wings which lie under the wing-cases are folded up on themselves, and when spread out are much larger than the wing-cases. The wings are transparent and very delicate. In _Corixae_ the posterior wings, which lie under the hard and h.o.r.n.y anterior wings, are a little shorter than the anterior wings; they are not folded up on themselves and are not so delicate and transparent as the wings of the beetle.

Such small creatures as _Daphnia pulex_, _Cyclops quadricornis_ and _Rotifera_ should be introduced into ponds.

Snails (_Gasteropoda_) may be roughly divided into three cla.s.ses, according to the shape of their sh.e.l.ls: (1) Flat-shaped coils (type _Planorbis corneus_); (2) Oblong-shaped, somewhat like a trumpet (type _Limnaea stagnalis_); and (3) Ear-shaped (type _Limnaea auricularia_).

_Limnaea auricularia_ is particularly suitable for deep waters, and _L.

pereger_, whose sh.e.l.l is of type 2, is a most valuable addition to the food supply in any fish pond. It is one of the commonest of our fresh-water snails.

Mussels (_Conchifera_) are another valuable article of food. There are a great many different kinds, and the larger ones should, as a rule, be avoided. _Sphaeriidae_ and _Pisidia_ are probably the best.

In many cases it is advisable to attempt the introduction of some flies which are not present. There are several cases in which the May-fly has been successfully introduced, and also the Grannom. Small _Ephemeridae_ seem to me preferable to any other flies.

With regard to suitable plants for comparatively deep water in ponds or lakes, lakewort and stonewort grow on the bottom, and do not, as a rule, attain any considerable height. White and yellow water-lilies also grow in fairly deep water; the water-lobelia is also an excellent plant for ponds.

In streams some of the best plants are water-crowfoot, water-starwort, and the great water moss. Anacharis should not be introduced into any water, either pond or stream, unless it can be kept down easily. It will otherwise become an unmitigated nuisance.

Marginal plants are a very important consideration, and plenty of them should be grown. Water-celery and water-cress are perhaps the best food-producing marginal plants that can be grown. Bullrushes and brooklime are also good, but the bullrushes must be planted judiciously.

CHAPTER III

SUITABLE FISH AND SUITABLE WATERS

Having stocked his water with suitable vegetation and food, the next matter which should engage the attention of the amateur, is what fish he had better introduce. He should, where there is a fair chance of success, introduce a trout of some sort, as they give better sport than coa.r.s.e fish.

The introduction of salmon into a river is not likely to be attempted by the amateur, but the head of salmon frequenting a river is undoubtedly affected in the most marvellous manner by artificial means. In Canada and the United States this is particularly remarkable, but the operations are conducted on a gigantic scale.