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Full text of "Leaflet"

Digitized by the Internet Archive 

in 2012 with funding from 

Royal Ontario Museum 



http://archive.org/details/leafletr06roya 



ROYAL ONTARIO MUSEUM OF ZOOLOGY 

TORONTO 
LEAFLET NO. 6* 

THE EASTERN SPECKLED TROUT 

(Salvelinus fontinalis) 

NO outing is more popular among those who love angling than to get 
away for a day's fishing for speckled trout. There was a time 
when good trout fishing could be found within easy reach of almost 
every part of Ontario and other provinces of Eastern Canada, but the 
trout has gradually disappeared from so many of the streams in the older 
settled districts, that now it is necessary for most of us to go long 
distances to indulge in this splendid sport. 




THE EASTERN SPECKLED TROUT 
The mottled back and the almost square cut tail distinguish the speckled trout 
from the lake trout in which the back is uniformly coloured and the tail deeply- 
forked. 

The speckled trout owes its popularity to several features. No fish 
surpasses it in beauty. While the fish vary widely in coloration even in 
the same waters, all have scattered over their sides a number of brilliant 
red spots surrounded by rings of blue. It is to these spots that it owes 
its common name. Usually the general colour is dark green with darker 
mottlings on the back. In late summer and in autumn, the lower sides of 
the males are a flaming red. The speckled trout is a gamy fish, that is, 
it fights to get away when it is hooked, and does not give up and allow 
itself to be pulled in like a stick or old boot. Then too, its flesh is tasty. 

'Reprinted from THE SCHOOL, October, 1936. 

1 



While game fish are sought more for the sport of catching them than for 
the food to be derived from their flesh, yet a game species whose flesh is 
delicately flavoured has an added claim to popularity. Another feature 
which enhances the charm of the speckled trout is the attractiveness of 
the conditions under which it is found. It is a fish of cool, unspoiled 
streams, especially those of some current, flowing through natural country. 
In the spring and early summer, when speckled trout fishing is at its best, 
it is refreshing to follow such a stream in search of fish, to see the birds 
and other wild creatures found in such places, and to enjoy nature at 
its best. 

If we can bring back the trout to streams from which they have 
disappeared, and keep them plentiful in waters where they still occur, 
it will add a great deal to the attractiveness of our country. 

Some people believe that there are different kinds of speckled trout 
because trout from different localities vary so much, especially in size 
and coloration. Most of these differences are due to the conditions under 
which the fish live. Thus fish in clear, cold streams are bright greenish ; 
fish in brownish water flowing from boggy places where there is much 
decaying vegetation are brownish, and trout that go into salt water, as they 
often do in the region of the Gulf of St. Lawrence and the Maritime 
Provinces, become quite silvery after a sojourn in the sea. Similarly fish 
in small streams where there is little food, often do not grow more than 
seven or eight inches in length, no matter how long they live, whereas 
trout in large rivers sometimes reach a weight of several pounds. So far 
as known, there is only one species of eastern speckled trout, the differ- 
ences in colour, size, body shape, etc., being due to differences in the 
character of the water and the amount of food available. 

In waters producing an abundance of food, the trout grow to a size 
of five or six pounds, or even more, but where food is scarce they mature 
at a length of seven or eight inches. If a bird or mammal does not get 
enough food, it dies or becomes stunted and abnormal, but fish are 
different. When food is scarce, fish cease growing, but this does not 
interfere seriously with their normal life history; young are produced 
and the species carries on quite successfully at the smaller size. The 
largest weight recorded for a speckled trout is fourteen and a half 
pounds. This fish was taken in the Nipigon river in 1915. 

Speckled trout cannot live in warm water, and that is the reason for 
their disappearance from some of the streams in which they once thrived. 
Formerly, these streams flowed through forests or between banks shaded 
by shrubs and bushes. Now the sun beats directly on the stream, warming 
the water above the temperature at which trout can survive. When the 
forest is cleared away and the fields are cultivated, the stream is flooded 



with muddy water in spring; and trout will not live in water earrying a 
load of sediment. If most of the water which falls as snow or rain 
quickly rims away as floods, there is little to maintain the flow in summer 
and the stream contains very little water at that season. This is harmful 
in several ways. Fewer fish can live in a small amount of water than in 
a large one, a small quantity of water will be raised to a higher tempera- 
ture by the same heat than a large quantity, and, as we shall see later, the 
same amount of pollution is more injurious in a small stream than in a 
large one. 

The pollution of our streams by running into them various wastes 
from mills and factories also serves to make them unsuitable places for 
trout to live. Some of the materials that are being placed in our streams 
are waste liquids from gas plants, galvanizing establishments, dye works, 
steel mills, woollen mills, creameries, slaughter houses, chemical factories, 
paper mills, and mines. Some of these materials are injurious to fish by 
removing the oxygen from the water; others are poisonous to them. 

A fish must secure oxygen to support its life. An animal on land 
obtains its oxygen from the air it breathes. In the lung, the oxygen passes 
into the blood through the thin walls of the blood vessels. There is a 
good deal of oxygen dissolved in the w r ater of most lakes and streams, and 
this oxygen passes into the blood of the fish through the thin walls of 
the blood vessels of the gills. Oxygen can be removed from water by 
boiling it. If a fish is placed in water that has been boiled and then cooled, 
it will soon die, just as a mouse dies if placed in a bottle from which all 
air has been removed. Some kinds of fish can live in water containing 
very little oxygen, but trout will live only in waters of high oxygen 
content. Some substances placed in streams are injurious to fish because 
they remove the oxygen from the water. Wastes from creameries, which 
at first thought would not appear to be harmful, reduce the oxygen content 
of the water and render it unsuitable for trout. A small amount of 
pollution in a large river may not be serious, but where many factories 
pour waste materials into a stream whose flow has shrunken to only a 
fraction of its former volume, conditions are made very difficult or 
impossible for such fish as trout, which require clear, cold, well-oxygenated 
waters. 

Many streams in which trout were once found, now contain only 
chubs, suckers, and other coarse fish. It is sometimes thought that the 
coming of the chubs and suckers has driven out the trout. This is 
usually not the case. What happens is that the stream becomes unsuitable 
for trout, and as the trout die out, coarse fish come in. 

In some streams where conditions are still favourable for trout, there 
are not as many fish as there should be because of over-fishing. If too 

3 



few adult trout are left in the streams, the production of young is not 
sufficient to keep up the supply. The number of fish which we can take 
from a lake or stream year after year is limited, just as it is in the case 
of domestic animals on a farm. If we kill more than the natural increase 
each year, the stock will gradually be reduced. An account of ihe repro- 
duction of the trout will help in understanding how the population is 
maintained. The speckled trout spawns (deposits its eggs) in the fall, 
usually in October ; but in some areas it is much later. Most of the fish 
move upstream at this time and bury their eggs in the sand or gravel of 
the stream bed. From these eggs, small trout about half an inch long 
hatch in late February or March. At first they are very helpless ; and if 
they are unable to find enough of the tiny animals on which they feed, or 
if they cannot conceal themselves, many of them die of starvation or are 
eaten by enemies. There is so enormous a loss at this stage, that from 
several hundred eggs produced by each female, only a few dozen trout 
reach a size of two or three inches. There is not much that can be done 
to reduce this loss under natural conditions in a stream. In hatcheries the 
little fish are protected from enemies and given sufficient food, so that a 
much higher percentage of the eggs produce young trout. It is impossible 
to eliminate all the enemies of young trout in a stream. They are preyed 
on, for instance, by large predaceous insects, and sometimes by water 
spiders. Perhaps their worst enemies are the larger trout. If there are 
more trout in a stream than can find food, the big ones eat the little ones. 
There is a definite limit to the number of trout which any body of water 
can support, and that number is determined in large measure by the food 
available for trout of different sizes. 

If conditions in a stream have been changed by removal of the forest, 
by pollution, or by other means, so that trout cannot find food or shelter, 
or if the temperature becomes too high in summer, it is useless to place 
fish raised in hatcheries in the stream. Hatcheries can only help increase 
the fish in a stream or lake, when conditions in the water are such that 
more fish can live there than are produced naturally. The chief means 
that can be employed for the conservation of speckled trout is to restore 
or maintain suitable conditions in streams and other waters where this 
species can live, and then to limit the catch to a number which can be taken 
year after year without reducing the supply. 

J. R. D.