April 2, 1900.] THE TROPICAL AGRICULTUEIST. 
685 
NEW TROUT-FISHEKIES. 
The following extracts from a paper in Black- 
wood for Felirnary (liy John Bicker:lyke) will 
be read with interest by many in Ceylon where 
so much is done to introrluce Trout into our 
streams : — 
At a time when agiioullural land is in many places 
Tinproduclive of income, while trout-lisheries, gore 
particularly those in the neighbourhood of big towns, 
will fetch enormous rents, the utilisation of ponds, 
lakes, and streams as fi-heries is well worthy of con- 
sideration by all land-ownex's who have watsr of any 
kind on their estates. There is a popular belief — like 
many others, a mistaken one — that trout cannot be 
reared except in running water. As a matter of fact, 
there is hardly any piece of unpolluted waiter, stag- 
nant or flowing, in which trout may not be raised, 
provided the fiah can obtain, either in the water itself 
or from the hands of the keeper, a sufhcient supply 
of food. 
But while a stagnant pool may be made a rearing- 
ground for large, lusty trout, it should be well under- 
stood that for these trout to aaturally increase their 
species running waier is necessary. This fact, however, 
need be no obstacle in the way of trout-culture ; for 
where the fish in any pool cannot increase naturally, 
it is an inexpensive and simple matter to keep restock- 
ing the water from oiher sources. 
In many large lakes trout, salmon, pike, perch, 
and eels live together on fairly amicable terms, each 
taking toll of the other, with the result that while 
trout are not plentiful, they are, on the other hand, 
very large and, as a rule, in splendid condition. 
There is, however, one great disadvantage in having 
trout with coarse fish in the water— the trout do not 
rise well. They may betaken by trolliug all through 
the season, but if they rise at all, it is only when 
the may-fly, or green-drake as it is called in Ireland, 
brings them to the surface. 
Exactly the same state of affairs may be found in 
rivers where coarse fish abound. The greater the 
number of coarse fish, the larger the trout, and the 
fewer the opportunities of the fly-fisher. These facts 
point very strongly, and indeed unmistakably, to the 
necessity for abolishing coarse fish from those rivers 
and lakes in which it is desired to have free-rising 
trout. 
i would like here incidentally to comment on the 
mistake so many fly-fishermen make of returning to 
the water what they term out-of-condition trout. 
When black-looking, lanky ti.^h of a foot or so in 
length are caught, particularly if about the middle of 
May is passed, the best thing to do is to knock them 
on the head, for they wili surely be old or diseased, 
and are better out of the river. 
In addition to taking out the coarse fish, the shal- 
lows of the stream should be harrowed and made as 
clean as possible — a process which may be repented 
with advantage every summer. If there are any lay- 
bys where black, stinking mnd has collected, the filth 
should be altogether removed and spread on the laud. 
It makes excellent manure. Light-coloured, clean, 
sandy mud, on the other hand, harbours the larvce of 
waterflies and other fish food, and should not be 
wantonly disturbed. Large^reed beds, as I have said, 
are better put out of the way, for they are cover for 
pike. I do not mean by this the wholesale cutting 
down or sweeping away of all rushes, reeds, sedge, and 
weeds. A reasonable ixuantity of these growths is 
necessary to serve both as shelter for the trout, and 
breeding and resting-places for the thousanJ-and one 
small cieatures on which the trout feed. 
As trout, after they are introduced, will be found 
spawning in the autumn and winter, great care 
should be taken to leave the bed of the river, and 
the mud at its sides, carefully alone during that 
season. Nothing is more faial to the healthy hatching 
of the eggs than disturbance of any kind, or the 
dirtying of the water, caused so often by men wad- 
ing in the river, netting, dredging, and similar 
operations. I have not the least doubt that works 
and repairs carriisd ou at mills during the spawning 
iseason entail the loss of thousands of prospective trout. 
The sediment in the dirty water sent down settles 
on the redds (gravelly shallows where the trout have 
been spawning) and chokes the eggs. A trout egg is 
a most delicate thing. It may be said to breathe 
in the water, being full of tiny pores from which car- ' 
bonic acid gas is given off. If these pores are choked 
with the sediment deposited from the stream, the 
embryo within the egg is asphyxiated by its own 
carbonic acid gas which it is no longer able to get rid 
of. For this reason a trout-egg so near hatching that 
the eyes of the young fish can be seen, if placed in 
still water, will die in a few hours, the water imme- 
diately next to it quickly becoming charged with 
poisonous oarbjnic acid gas. The owner of a trout- 
stream should therefore use his utmost endeavours 
to maintain the purity and flow of the water during 
the spawning season. Once the fish are hatched and 
feeding, the sediment, and even a certain amount of 
sewage pollution, matters little. Indeed, in sewnge- 
poUuted rivers trout often thrive exceedingly, though 
they are unable to breed ; and of this the Wandle, 
near London, is a remarkable Instance. 
Ponds and lakes into which no water flows are as 
useless for breediug fish as a polluted river ; but such 
sheets of water may b- treated in much the same way 
as the stream. In the first place, the coarse fish should 
be removed. Next, if the bottom is muddy and capable 
of being cleaned, the cleaning should be done, except 
in places where it is desirable to cultivate weeds, and 
with them the food of trout. When the water is ready 
for them trout should be turned in from time to time. 
The sheets of water not included in the terms " river " 
and " stream," which are likely to yield the best 
results, are those which have naturally a gravelly 
bottom, with aquatic growths near the edges, and here 
and there rocks; and, secondly, pools which are 
capable of being emptied. These latter are mostly of 
artificial construction, and, as a rule, have been 
brought into existence, at some time or another, by 
means of a dam thrown across the course of some 
small stream, the object often being to obtain water- 
power. Even though the bottom be of mnd, trout 
will thrive; but it is most desirable to occasionally draw 
off the wa er, dry the pond, and expose it to the air for 
a few months. The fish-culturists of Catholic times 
when there were no means of transit for sea fish, and' 
fastdays had to be provided for, used to grow a crop on 
the bottom of their ponds from time to time. The 
earthy bottom having been sweetened and purified by 
light and air, water was turned in, and fish introduced. 
The exatuple is one to be followed, 
Sheets of water which I should deem entirely 
unsuitable for trout are those which are very shallow, 
and in which the temperature rises considerably in hot 
weather. If there is a. stream flowing throtigh such a 
piece of water, and a considerable growth of weeds 
among which the trout can take shelter from the sun 
then fish may thrive : but be it well understood that 
trout must have shelter, either under overhanging 
banks, in deep water, under weeds, among rocks, or 
behind old camp-sheathing. The reason why so many 
amateurs fails in their attempt to rear trout-fry is that 
they place them in quite shallow ponds of small area 
exposed to the fall light of the sun— ponds in which 
the temperature of the water varies considerably 
and quickly. 
Lastly, 1 come to a consideration of the varieties of 
trout which may be introduced. This depends in ft 
large measure on the locality and the food-supply, 
natural or artificial. In Sir Thomas Wardle's famous 
pool in Staffordshire an immense qua.ntity of trout of 
various kinds are kept in a, healthy condition in a pool 
of probably not more than an acre in extent. The 
growth of weeds ii considerable, and the supply of 
water-snails, ahriinps, and other natural food seema 
almost unlimited ; but in addition the keeper throws 
in half a bucket or so of fish food every day, which is 
readily taken by the rainbows, fontinalis. Loch Leven 
trout, farios, and hybrids inhabiting the pool.jj 
I have no hesitation in saying that for ponds and 
other enclosed waters, where the temperature in 
winter is not a very low one, there is no variety of 
trout so escelleat as the rainbow (Halno imUix^ 
