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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 quantity 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 horny 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 classes,

according to the shape of their shells: (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 shell 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.



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