Trout are
usually found in cool, clear streams and
lakes, and are distributed naturally
throughout North America, northern Asia and
Europe. Several species of trout were
introduced to Australia and New Zealand by
amateur fishing enthusiasts in the 19th
century, contributing to the displacement of
native freshwater fish to some extent.
Trout have fins entirely without spines, and
all of them have a small adipose (fatty) fin
along the back, near the tail. There are
many species, and even more populations that
are isolated from each other and
morphologically different. However, many of
these distinct populations show no
significant genetic differences, and
therefore what may appear to be a large
number of species is considered a much
smaller number of distinct species by most
ichthyologists.
The trout found in the eastern United States
are a good example of this. The brook trout,
the aurora trout and the (extinct) silver
trout all have physical characteristics and
colourations that distinguish them, yet
genetic analysis shows that they are one
species, Salvelinus fontinalis.
Lake trout (Salvelinus namaycush), like
brook trout, actually belong to the char
genus. Lake trout inhabit many of the larger
lakes in North America and live much longer
than rainbow trout which have an average
maximum life span of 7 years. Lake trout can
live many decades and can grow to more than
60 pounds (27 kg).
Most trout are
restricted to fresh water, but many, like
the steelhead (Oncorhynchus mykiss) – which
is the same species as the landlocked
rainbow trout – spend their adult life in
the ocean and then return to spawn in the
streams in which they were hatched. This is
called anadromous reproduction and is more
often seen in salmon. Brook trout, brown
trout, cutthroat trout, bull trout, and
Arctic char also have populations that run
to salt water.
Trout generally feed on soft bodied aquatic
invertebrates, such as Diptera, mayfly,
caddis fly, and stonefly, although larger
specimens of trout regularly feed on other
fish.
As a group, trout are somewhat bony, but the
flesh is generally considered good eating.
Additionally, they provide a good fight when
caught with a hook and line, and are sought
after recreationally. Because of their
popularity, trout are often raised on fish
farms and planted into heavily fished waters
in an effort to mask the effects of
overfishing. While they can be caught with a
normal rod and reel, fly fishing is a
distinctive method developed primarily for
trout and now extended to other species.
Farmed trout and char are also sold
commercially as food fish.
Trout that live in different environments
can have dramatically different colorations
and patterns. Mostly, these colors and
patterns form as camouflage, based on the
surroundings, and will change as the fish
moves to different habitats. Trout in, or
newly returned from the sea, can look very
silvery, while the same "genetic" fish
living in a small stream or in an alpine
lake could have pronounced greenish speckles
with far more coloration. It is virtually
impossible to define a particular color
pattern as belonging to a specific breed,
however, in general, wild fish are claimed
to have more vivid colors and patterns.
The cutthroat trout has 14 recognized
subspecies (depending on your sources), such
as the Lahontan cutthroat trout Oncorhynchus
clarki henshawi, Bonneville cutthroat trout
Oncorhynchus clarki utah, Colorado River
cutthroat trout, Yellowstone cutthroat
trout. |
Trout
is the common name given to a number of
species of freshwater fish belonging to the
salmon family, Salmonidae.
