NOTES ON RAINBOW TROUT.
RAINBOWS are a comparatively recent importation into our native
waters, and appeared just at the time when they were most needed. It
is but a few years since our British waters, neglected, except in a
few instances, began to receive the attention they deserved, in view
of their intrinsic value. Steps were then taken to diminish, if not
entirely to remove, the terribly universal pollution of our streams
and rivers. From that time trout fishing prospects in river and stream
began to look up and improve; but our ponds and reservoirs, if stocked
with fish at all, contained only the coarse fish of former times. By
a happy coincidence the rainbow trout, which we owe to our cousins of
the United States, began to be talked about and known. Speedily our
fish-culturists took them up and established them in their hatcheries,
with the best results. A more sporting or gamer fish does not exist. He
rises most freely to the fly--up to a certain weight--and, when hooked,
plays as gamely as any sea trout. He grows with astonishing rapidity.
In our local waters, two-year-old fish, 8 in. long in February, have
grown to ¾ lb. fish and even to pounders in September. There is
therefore no excuse for leaving our ponds untenanted by these gamesome
fish. Moreover, their edible qualities are quite first-rate; they are
shapely, beautiful in colouring, and thrive in any kind of water. One
point, however, should be carefully guarded against. Rainbows are great
travellers; they will push up, especially before spawning, and it is
therefore necessary to confine them by a grid at the head and foot of
your water.
The spawning time for these fish in their natural habitat is rather
late in the spring; but, as might be expected from analogy, rainbows
bred and reared in this country appear to be adapting themselves to
their environment, and to be gradually assimilating their time for
spawning to that of our local trout. The bulk of rainbows spawn in
British waters about February and March, many retain their old times
of May and June, whilst a proportion have adapted themselves to their
surroundings and spawn as early as brook trout. I think that the date
is more or less influenced by the amount of fish food obtainable. Thus,
for instance, with hand-fed fish the old later dates are maintained;
but it is still doubtful, as far as my experience goes, as to whether
the ova of the fish that are dependent entirely upon natural food
is ever vivified. My fish undoubtedly have spawned on the prepared
beds, but, so far, I have not been able to establish any evidence
of matured fry. The edges of the water this summer were filled with
multitudinous small fry no doubt, but on careful inspection they proved
to be entirely the fry of sticklebacks, perch, &c. I have found hen
fish gravid with ova as early as November and as late as April. In
time, no doubt, their spawning season will coincide with that of our
brown trout. And herein lies a field for investigation and careful
watching. It is held in many quarters that rainbows do not breed in
Great Britain. My experience hardly tallies with this belief. On our
waters in Lancashire, where we had no gravel beds suitable for the
deposit of ova, I found late last year several hen fish, of from 1½ lb.
to 2 lb. in weight, dead in the water; they were full of ripe ova, and
had undoubtedly died through being egg-bound. I then made some spawning
redds suitable for the deposit and fertilisation of the ova, and it
has been highly interesting to see the fish elbowing each other to
secure a spot for themselves. Since then I have caught many spent fish,
both cock and hen, showing that the ova, at any rate, have been duly
deposited; but so far I have not been able to identify the fry. A large
quantity of fry of sorts I have secured this season, but they proved to
be the fry of stickleback. The "Trinity" two-year-old fish I restocked
with seem to be growing admirably. This form of rainbow trout have
the reputation of being, if possible, freer risers, quicker growers,
and harder fighters than the ordinary kind; so far they seem to act up
to their reputation. The few I have caught fought like little demons,
and it was almost difficult to be able to restore them to the water
and free the hook before they had been practically exhausted by their
frantic efforts for freedom.
The proper amount of fish with which to stock a given area of water
depends several circumstances. First and foremost, of course, it
depends upon the amount of fish food in it. Many pools and ponds are
full of fresh-water shrimps, snails, and the like, all of which are
of very great value in developing and fattening your fish. But as you
do not want to depend upon bottom feeding for their whole stock of
food, admirable adjunct though it may be, it is well to place round
the margins of your waters all plants that encourage the increase
of fly food. Beds of the ordinary watercress are not only valuable
in this respect, but afford welcome shelter. Water lilies, if kept
within bounds, are equally valuable, and it must never be forgotten
that, especially in shallow water, shelter from the summer sun is an
absolute necessity if you wish your stock to improve. Other aquatic
and semi-aquatic plants should also be utilised freely, such as marsh
marigolds, starworts, bulrushes, &c. Nor should it be forgotten
to plant alders and fringing willows here and there. All trout,
particularly rainbows, take an alder fly readily.
A certain area of water will not support more than a certain weight
of fish life. You can therefore either have that weight made up by a
large quantity of small fish or by a correspondingly smaller number of
larger fish. It is not prudent, therefore, to overstock. This question
has necessarily very considerable bearing upon your calculations. Nor
is it possible to fix arbitrarily any precise number of fish as being
capable of being supported by a given area of water; an examination of
the water itself would be needed to determine this with any degree of
accuracy.
Having, however, once determined upon the proper stock required--and,
in my opinion, it pays better to stock with two-year-old fish than
with yearlings--then an accurate account should be kept of the fish
taken out of the water each season, and a corresponding number should
be turned in each November for restocking, a few being added for
contingencies.
As I have already stated, when rainbows grow into really big fish--say
over 2½ lb.--they appear, in our British waters, to develop lazy,
bottom-feeding proclivities. It will be necessary, therefore, or at
any rate advisable, to take these fish out by using a bright salmon
fly, fished deep, or a minnow, fished as deep as the water will admit.
When the fish are first placed in their fresh home it is customary
to feed them with artificial food until they get accustomed to their
surroundings. For this purpose liver is often used, and it is quite an
amusing sight to see them "boil" when such food is distributed. It is
very doubtful whether it is wise to feed with such fat-producing foods.
Some authorities hold that fatty foods of any kind produce disease of
the liver and fatty degeneration, and condemn absolutely all red meat.
If this be so--and it appears to be not only probable, but proved by
expert experience--it is better to let the fish take care of themselves
and eschew all kinds of artificial food stuffs.
When stocking, every care should be taken to see that when the fish
arrive they are placed as soon as possible where the water is most
lively and broken, so that they may, at the earliest practicable
moment, obtain the air they so much need after their journey. The water
in the cans should never be allowed to stagnate. One more precaution
is indispensable, viz., to see, by means of a thermometer, that the
temperature of the water in the stream or pond is the same as that in
the cans. If there should be any difference--and there will almost
certainly be--it can easily be adjusted by letting some water out of
the cans and substituting that of the stream. By doing this gradually
the fish will become acclimatised to the change. The cans on the cart,
meanwhile, should be agitated, and therefore aerated, by keeping the
cart on the move. Neglect of this will cause serious risk of loss.
Once safely deposited in their new home, the fish will speedily spread
over your whole water, even if all were put in at one spot. Perhaps
it is unnecessary to add that fish should never be handled when being
put into the water. A small flat net will pick up any that may have
fallen on the ground during the change of water. It is surprising
how thoughtless many people are about handling and treating fish.
Thus, for instance, if an undersized fish is caught it is, in common
parlance, "thrown back," and is often in reality so treated. Too much
care cannot be taken in replacing fish. If put back gently and held for
a few seconds in a proper position, back up, they will soon recover
from their exhaustion and glide away unharmed; whereas, if "thrown
in," or dropped in in a careless manner, they will turn belly up, and
probably never recover.
When all precautions are taken, and your waters have been intelligently
treated, and suitable spawning redds are provided, you will never
regret having stocked with rainbows, for the sport you will obtain from
them will more than amply repay you for the trouble you may have taken.
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