Amateur Fish Culture Part 3

When the time came to set my little fish free in the rearing ponds, as a matter of principle I covered the ponds with herring-net, closely pegged down on the banks so that I could not even get my hand under the edge. I did not think that there were any kingfishers or herons about, and so was very surprised when one morning, on going down to feed the fish, I found a kingfisher under the net, flying up and down the pond trying to get out. By carefully introducing a landing-net under the netting over the pond, I was able to catch the intruder, and caught four more in the same way in about three weeks. Since that time I have not agreed with the people who have stated that the kingfisher is almost extinct, at least in that part of the country. I may say that there are but few streams there, and that it is not at all an apparently likely place for kingfishers. I am quite sure that wherever any one begins to rear fish there he will find that kingfishers are fairly common. The amateur will probably be also surprised at the way herons appear, if he conducts his fish-rearing operations, as he should do, in a secluded spot.

Many of the directions I gave as to the management of the fry and the rearing boxes, apply also to the fry after they have been turned out into the ponds. The doses of earth should still be given regularly, and salt may be applied also in the way I have already described. The little fish will be found to scatter over the pond or to divide again into two bodies, one at the upper and one at the lower end of the pond, as they did in the boxes. The fish culturist should try to induce these fish to come to the head of the pond as much as possible. It is a good thing to place some boards across the head of the pond to give shade and shelter to the fry. It will probably be found that if much artificial food is given to the little fish, a sc.u.m will be formed on the surface of the water. This sc.u.m is composed of grease, and should be removed, as soon as it is observed, with a gauze net.

All the time that these operations have been going on with regard to the little fish themselves, due attention should have been given to the vegetation round the ponds. The alders and willows which I before recommended to be planted round the ponds should be induced as much as possible to overhang the water. Gra.s.s and other vegetation should be allowed to grow freely round the margins, as many insects are then likely to fall into the water.

This vegetation will supply the little fish with a certain amount of natural floating food, without any interference on the part of the fish culturist; but he should, however, give them other floating food, both natural and artificial, as much as possible, for this will get them in their youth to adopt the habit of feeding freely at the surface. When the alders and willows have grown sufficiently and are well covered with leaves, they will probably give enough shelter to the fish to make the boards at the upper end of the pond unnecessary.

As time goes on, and the little fish grow, they should be thinned out, the smaller and weaker being removed into another pond. Despite the best endeavours of the fish culturist, a certain number of these small fish are sure to keep to the lower end of the pond, and it is these which should be removed first. If they are left, the difference in size between the smaller and the larger will soon become so great that the large fish will very likely be tempted to eat the small ones, thus developing a cannibalistic habit which they will keep always.

At the end of August or the beginning of September the little fish will have got over the most dangerous part of their lives. After this time they are called yearlings, are much more hardy and not subject to nearly as many risks as up to that time.

The great points to remember are:--That the food should be varied as much as possible; and as much natural food, of a hard description such as shrimps, _corixae_, snails, bivalves, etc., be given. That the little fish should be well protected from enemies. That they should not be over-crowded, but the weakly and small fish be separated from the larger fish. That frequent doses of earth should be given to keep the bottom sweet and clean.[2] That the inlets and outlets should be frequently cleaned and kept clear, to ensure a good flow of water through the ponds, and that a careful watch should be kept for such misfortunes as fungus and dead fish, in order that they may be dealt with at once.

[2] See two letters in Appendix.--Page 93

CHAPTER IX

TROUT. THE FRIENDS AND ENEMIES OF THE FISH CULTURIST

The creatures which are sometimes found in and around rearing ponds containing ova or young fish are very numerous, and it is advisable that the fish culturist should have some knowledge of them. It is for this reason, that while I cautioned my readers against the creatures which are dangerous, and enumerated some of those most serviceable as food, I left detailed descriptions of these enemies and friends of the little fish, in order that I might deal with them in a separate chapter.

[Ill.u.s.tration: LARVA OF _DYTISCUS_ AND YOUNG TROUT.]

Among the worst enemies of both ova and fry is the _Dytiscus marginalis_, whether this insect be in the larval or adult stage. I think that I should hardly be wrong in going even further and saying that _D. marginalis_ is very dangerous to trout early in their yearling stage. The accompanying ill.u.s.tration shows a larva of _Dytiscus_ which has caught a young trout. This ill.u.s.tration is taken from a photograph of a specimen lent to me by Mr. F. M. Halford, and both the fish and the larva were alive when they were caught. Unfortunately the trout is a little shrivelled, and the legs of the _Dytiscus_ have been broken. _D. marginalis_ lays its eggs in the stems of rushes. The larva, when hatched, makes its way out, and proceeds to lead a predatory life.

The larva when full-grown is about two inches long, and is quite the most rapacious creature which lives in our waters. The adult beetle is also purely carnivorous, but is perhaps not quite so rapacious. It would, however, probably attack a larger fish.

The largest of English water beetles is _Hydrophilus piceus_. This beetle is not, in the adult stage at least, carnivorous, but the larva, which is about half an inch longer and considerably fatter than that of _D. marginalis_, is carnivorous. It may be told from the larva of _Dytiscus_ not only by its size, which is hardly a reliable point for discrimination, but by the smaller size of the head in comparison to the rest of the body. The claws, with which _Hydrophilus_ seizes its prey, are, too, considerably smaller than those of _Dytiscus_. This larva should be kept out of the rearing ponds with just as much care as that of the more voracious _D. marginalis_.

With the kingfisher I have already dealt at some length, so that I need say but little more with regard to it. One of the worst features in this bird's character is that it will go on killing many more little fish than it can possibly eat. As I have before said, it is surprising how these birds will appear in considerable numbers where a fish hatchery is started, even in localities where they have before been considered rare.

I have already described how the ponds should be protected from their ravages.

Herons do a great deal of harm to fish ponds, even when the fish have got well into the yearling stage. I have on one or two occasions known of herons wounding trout of at least a pound in weight. Besides the actual damage they do by killing fish, they put all the other fish in the pond off their feed through frightening them. After a heron or kingfisher has been about a rearing pond the little fish will not feed for a considerable time, sometimes even for days. Notwithstanding their very evil proclivities, both herons and kingfishers are very interesting. A kingfisher, if he catches a fish which is a little too big for him to swallow whole, will knock the head of the fish, which he always catches by the middle of the body, against a stone, in order to kill it, or at least to stop it struggling; it might otherwise in its struggles escape, as the kingfisher can only swallow a fish head first.

There are stories which tell how herons sometimes pluck small feathers from their b.r.e.a.s.t.s and, floating these feathers upon the water, catch the trout as they rise to it; it is supposed that the trout takes the feather for a fly. Personally, I do not think that much credence should be attached to the latter story.

Other birds, usually found on or near the water, are also likely to do much harm to the ova and young fish. Almost every creature which is found near the water seems to have a great liking for the ova of fishes.

All the wading and swimming birds are to be dreaded by the fish culturist. They will, all of them, eat ova in enormous quant.i.ties, and many of them will also eat the little fish.

Besides birds, small larvae of several insects will eat, or at any rate kill, the ova in considerable numbers. Caddis-worms are among these larvae which eat ova. This seems to be one of the few cases in which nature is just, for caddis-worms are taken very readily by even small trout. Large trout will take them very greedily, cases and all.

Therefore, I should advise the fish culturist to cultivate them as food for the fish he is rearing, but to be very careful that they do not get into the rearing boxes or hatching trays when he has ova in them. The caddis-worms kill the ova by making a small hole in them and sucking some of the contents out; from this hole some more of the contents escapes, and as it comes into contact with the water becomes opaque.

Caddis-worms are the larvae of an order of four-winged flies commonly known as sedges, caddis-flies, or water-moths. The latter appellation is of course a misnomer, as these flies (_Trichoptera_) have nothing whatever to do with moths. They resemble moths, however, in that they have four wings which when at rest lie in much the same position as do those of moths, and as many of them have their wings thickly covered with hairs, this resemblance is sometimes very marked. The larvae (caddis-worms), being eagerly sought as food by many fish, and having very soft bodies, make for themselves cases. Some of these cases are made from small sticks, some from little pieces of stone or sand, and some from a mixture of all of these substances. As these cases resemble such small pieces of rubbish as are frequently found in streams, care should be taken that they do not get into the hatching trays containing ova.

Many of the water beetles, and practically all of their larvae, will attack the ova; they should therefore be carefully excluded from the hatching trays. As there are about 114 different species of beetles in the family of _Dytiscidae_ alone, my readers will appreciate my reason for not attempting to enumerate them. It will be a sufficient warning to state the fact that they are all carnivorous, and their relative sizes is the only thing which will decide whether the beetle will eat the fish, or the fish the beetle.

Very similar to beetles are some of the water-bugs. They may, however, easily be distinguished from beetles, as the outer or anterior wings of the bugs cross each other at their lower ends, while the elytra of beetles, which much resemble the h.o.r.n.y, anterior wings of some of the water-bugs, meet exactly in the middle line. These water-bugs, though some of them are excellent food for even the small fish, will attack the ova, and therefore they should be kept out of the hatching trays. The fish culturist should, however, whenever it is possible, cultivate such of these water-bugs as are good food for the fry in separate ponds, as I have before recommended. The best of these water-bugs are _Corixae_.

Others, such as the water-boatman, water-scorpions and pond-skaters, are not of any value as food for the fish.

The larvae of _Ephemeridae_ are very good food for the fish, and should be cultivated in separate ponds if possible, and some turned into the ponds containing the little fish occasionally. A fair proportion should, however, be kept in the ponds and protected, so that a good stock of the flies may be available next year.

The larvae of _Ephemeridae_ may be obtained in many streams, and are best caught with a fine gauze net. Some of them swim, but most are generally captured with such a net at the bottom of the water among the _debris_.

Eggs of _Ephemeridae_ may be obtained sometimes from another locality if they cannot be got on the spot. These should be carefully preserved for the first year at any rate, and a good fly may thus be introduced into a water where it was before unknown.

I have already spoken of the fresh-water shrimp and the water-flea (_Daphnia pulex_). These valuable articles of diet should be introduced whenever it is possible. _Daphnia_ must be reared in a stagnant pond, the fresh-water shrimp (_Gammarus pulex_) in running water, with plenty of weeds.

Other useful creatures besides those snails and mussels which I described in a previous chapter, are the water-louse (_Asellus aquaticus_), _Cypridae_, and _Cyclops quadricornis_. Asellus is very similar in size and shape to the common garden-louse, which is found in decaying wood. It will live either in stagnant or running water.

_Cypridae_ are very much smaller, being generally only as large as a large pin's head. They have a bivalve sh.e.l.l which makes them look something like a small mussel. They are, however, very active, swimming by means of two pairs of legs. They also possess two pairs of antennae and one eye. (The species belonging to the genus _Candona_ of the family _Cypridae_, do not swim.) _Cyclops_ is another very small crustacean, shaped like a large-headed club. It swims very actively, and, like the _Cypridae_, is an excellent article of diet for very young fish. Both these crustacea live in stagnant water, and must, therefore, be kept in a separate pond, whence they may be taken as required to be given to the fry.

CHAPTER X

TROUT. MANAGEMENT, FEEDING, AND TURNING OUT OF YEARLINGS

As I pointed out to my readers in Chapter VIII., the young trout have after August pa.s.sed the critical period of their existence, and may be considered safe and hardy. Naturally, as they get older, they require more food, but this need not be given so frequently as the fish grow older. While it was necessary to feed the fry at least four times a day, it will be found quite sufficient if the fish in August are fed only twice during the twenty-four hours. I must here again impress upon my reader the importance of feeding the trout upon as natural a food as possible. Their future well-being depends upon this, much more than is generally realized even by fish culturists. Of course, trout fed entirely upon soft food may turn out all right, particularly if they are turned out as very young yearlings, but it is better not to leave anything to chance and make sure of being on the safe side.

As was the case with the fry during the whole of the earlier part of their lives, the yearlings will divide into two more or less separate packs, though the fish may have been separated several times before in order to divide those which kept at the head from those which kept at the lower end of the pond. Those trout at the lower end must be coaxed to the upper end as much as possible, care being taken when feeding that all the fish get a fair share of food. Should any of the fish remain obstinately at the lower end, and those at the upper end outgrow them to a marked extent, the smaller ones must be again separated from the larger.

When, in September or October, the little fish have grown active and strong, they may be turned out into the water they are to occupy for the rest of their lives. There is really no reason why, if they are well-grown and strong, they should not be turned out in August if the water they have to be taken to is quite close to the rearing ponds, but if they have to be carried any distance, it is better to keep them in the rearing ponds for a few weeks longer, till the weather gets cool enough to make it quite safe to allow for a possible delay in the transit.

The turning out of the fish requires some little care. I have seen fish which had been sent by rail, poured out with the water contained in the cans, in as hurried a manner as possible. Though of course it is important to get the fish out of the cans used for transport as soon as is compatible with safety; still, undue haste in this operation is likely to do much harm. Young fish of any kind require delicate handling, and young trout particularly. The cans should, when possible, be partly emptied, and some water from that into which they are to be turned put into the can. This is of course not necessary if the rearing ponds are supplied from the same source as the water into which the fish are turned. The cans should then be partially immersed in the water, and the edges brought gradually below the surface. This allows the fish to swim out of the cans of their own accord, and the few which will not go out may be forced to do so by gently turning the can upside down.

It is a very good thing to give each of the fish a dose of salt before turning them out, particularly if they have travelled any distance. This is easily managed by catching the fish, a few at a time, in a landing-net from the travelling can, and then, instead of putting them straight into the water, putting them into a bucket of salt and water for a short time. Sea water is of course better if it is available. This does away with any risk of their developing fungus on the spots which have very likely got bruised during the journey.

The yearlings are best taken from the rearing ponds by netting them. A net which is more than broad enough to go across the rearing pond is necessary. Too many should not be taken out at a time in each haul of the net, as they are thus more likely to be injured or dropped on the ground. The amateur should not forget, that though the little fish will stand a good deal of moving about as long as they are in water, they are likely to be killed, or at least severely injured, by a shock, particularly if that shock is sustained while they are out of the water for a second or two during their being moved from one place to another.

If the amateur intends to keep any of his yearlings longer than December, he will have to make a larger pond. This pond need not be a long, narrow one like those in which the fry were kept. Though the fish of course still require a sufficient supply of well-aerated water, a larger pond without the same marked current through it will do perfectly well. They must be well fed, and if any grow markedly bigger than the rest these should be separated. If they are not well supplied with food they are very likely to try and eat each other, that is to say, the largest will try to eat the smallest.

CHAPTER XI

THE REARING OF THE RAINBOW TROUT, AMERICAN BROOK TROUT, AND CHAR

As the methods used in hatching out the ova and rearing the young fish are very similar in the case of different species of trout to those I have already described in dealing with the common trout (_Salmo fario_), I will confine myself to pointing out the most marked differences in the habits of such species as are suitable to our waters, and which are likely to be of use to the fish culturist. The salmon- or sea-trout will be dealt with under salmon.

First and foremost among the trout, excluding of course our own brown trout, I put the rainbow trout (_Salmo irideus_). There are several varieties of this species, but that which is now being so freely introduced into many waters in England is the McCloud River rainbow (_S.

irideus_, var. _shasta_). As I have before stated, the rainbow sp.a.w.ns long after the _S. fario_. It therefore will give the fly-fishermen good sport after the season for the common trout is over. It is a very free feeder, and grows more rapidly than our trout; great care must therefore be taken to give it plenty of food. I would draw my readers' attention particularly to this fact as to the feeding and quick-growing qualities of the rainbow, for they make it, if possible, even more necessary that the water into which they are turned should contain a good supply of food than it was in the case of the common trout; though even in the case of the common trout, this is quite the most important consideration in stocking a water with fish.

Another advantage possessed by the rainbow is, that it is less liable to the attacks of fungus than any other of the _Salmonidae_. Though, of course, this is not such an important consideration nowadays as it would have been even a few years ago, still it is one which deserves some consideration, particularly from the amateur. This freedom from fungus is very marked in the rainbow, for I know of a case where some dace suffering from fungus were put into a rearing pond containing a few rainbows. Though the dace died of the disease, the rainbows remained healthy and free from it. The amateur will probably receive the ova of the rainbow towards the end of April or during May. The ova should hatch out within a few days of their being received.