Salmo gairdneri is Latin for the salmon of
the Atlantic and gairdneri is after Dr. Gairdner, a naturalist
in the employ of the Hudson’s Bay Comp any prior to 1840.
Members of rainbow trout populations arc notably diverse. Their
variability in colour. spotting. body form and other
characteristics led taxonomists to create a number of separate
and distinct species.
Ontario record is 40.7 lbs
The steelhead rainbow can best be known by
its migration to the sea. Because of this tendency, it was
considered separate and distinct from the non-sea-going rainbow.
But, all members of the rainbow series are more or less
migratory. This tendency is strongest in those occupying coastal
waters, and weakest in those isolated for generations from their
The body of the rainbow trout is typically
trout-like, spindle-shaped and laterally compressed. The larger
specimens are deep-bodied. There are teeth in the jaws. tongue
and roof of mouth. Coloration of the body varies with
environment. The fish may be bluish, bluish green. greenish or
olive green on the back. silvery on the sides, and light below.
A pink lateral band of variable width runs
from behind the eye to the end of the tail. This band is a more
vivid red, or reddish purple. in mature fish, especially in
breeding males; hence the name “rainbow”. The top of the head.
dorsal. adipose, anal and caudal fins are profusely
black-spotted. There are no red spots. Rainbows in the Great
Lakes are quite silvery with inconspicuous spots. except on the
tail fin: hence the name “steelhead”.
Rainbow trout are native in the Pacific ocean from smith Alaska
to Mexico. Ascending coastal streams to spawn. Populations in
the interior lakes ascend tributary streams. Subsequent to 1874,
when McCloud River rainbows were first secured in California for
fish cultural purposes. they were distributed in boreal waters
of Europe. South Africa. Australia. New Zealand and eastern
From 1880 to 1895. the only rainbow trout
propagated and distributed in the east were raised from eggs
collected from rainbows inhabiting the McCloud River, one of the
headwater tributaries of the Sacramento River in California-
These possessed smaller scales than the so-called coastwise
rainbow trout. Later, difficulties in maintaining suitable
stocks of McCloud River trout developed, and additional eggs
were secured from Kiamatli River trout and. later. from Nevada
and Colorado. Thus. the rainbows propagated in the east
Visits to tributary streams of larger lakes are not confined to
the spawning migration. A run of this nature takes place in
autumn when the autumn rains beg in. Rainbows appear to remain
near river mouths during the winter to enter the streams with
the first spring flood When two or three years old (six to eight
inches in length), rainbows desert the stream and remain in the
lake until mature.
At spawning time, rainbows migrate upstream, seeking swift
waters and clean gravel. In Ontario, spawning takes place in the
spring, usually in April and May. By selecting early spawners
for breeding purposes at hatcheries, spawning may take place in
water of constant temperature as early as December through
January and February.
The rainbow trout is a popular fish because
of its fighting ability. dash and beauty. There is none finer.
When hooked. it leaps out of the water and rushes and twists
with dogged determination and amazing persistence.
It rises readily to the fly. Dry fly
fishermen allow the fly to float downstream with the current.
Slack of the line must be taken up to permit the angler to
strike fast. Casting out where rainbows are feeding in the
shallows of lakes is a pleasurable and rewarding pastime. Trout
up to four or five pounds are readily taken on the fly. Larger
ones are taken by minnows or by trolling.
Aquatic insects and their larvae are important in the diet of
rainbow trout. Especially mayflies. caddis flies, black flies
and stone flies. Leaf hoppers. grasshoppers. true bugs. alder
flies and other invertebrates (leeches, crayfish and scuds) also
make significant contributions to the diet. Minnows. suckers,
yellow perch. herring and whitefish are important in the diet of
large rainbows. Rainbow trout that spend a greater part of their
time in lakes grow more rapidly and reach a larger size than
those that remain permanently in streams. A similar difference
in the growth of sea-run migrants as compared with non-sea-run
migrants has been reported.