the fishing season I frequently hear other fly fishers comment about
the Rainbow Trout they have just caught. The comments usually follow
the theme of; how beautiful, how amazing, how fantastic or how well
it fought. But have you ever REALLY thought about the attributes of
this incredible fish?
consider that a moderate size Rainbow can accelerate from a standstill
to about 23 mph (or 37 kilometers per hour) in about one second. A
larger fish can get in an extra one or two mph. Almost instantly the
fish is traveling more than 33 feet per second and can maintain that
speed long enough to easily strip a hundred yards of line and backing
off your reel. Its no wonder that if a fly fisher is going to loose
a Rainbow, it usually happens within two or three seconds of being
hooked. Can you think of another member of the animal kingdom that
can reach that speed so quickly? Even those animals known for their
speed, such as the Cheetah or Greyhound, cannot accelerate that fast.
how strong is that Rainbow
Trout? A trout of three pounds can easily break a leader tested
to six-pound strength. That's double its body weight. I defy you to
break, rather than cut, monofilament tested to just your own body
weight. Few members of the animal kingdom can accomplish this feat
but some larger trout do this on a regular basis.
Trout are also known for their jumping ability. A Rainbow can easily
leap into the air three or four times its body length. In the animal
kingdom, jumping to a height of more than two body lengths is uncommon
even on dry land. The household Cat and a few other members of the
animal kingdom can make similar leaps but that doesn't detract from
this incredible ability. In human terms, the trout is jumping 18 to
24 feet into the air out of a swimming pool.
you ever thought about why the Rainbow is extremely agile, can stop
on a dime, or has teeth but doesn't chew? How does it change color
to match its surroundings or suck oxygen from water without clogging
its gills in underwater debris or how can it remain suspended in the
water column with virtually no fin movement? These can all be explained
but will have to wait for a longer article. The main point is that
even though all these physical attributes are amazing, the 'senses'
of a Rainbow Trout are even more amazing.
input received by a Rainbow is estimated to be 500 to 800 times more
acute than the sensory input received by a human. This fish can perceive
its surrounds to a degree that we can only imagine. The fish's brain
is entirely devoted to bodily functions and sensory input. It doesn't
possess a Cerebrum and yet is quick to learn from experience. The
Cerebrum is the center for thought and reasoning in humans.
of a Rainbow do not have eyelids. They are quite sensitive to bright
sunlight. A trout is somewhat near sighted but can see quite well
up to distances of about twenty feet. Sight is used to locate food
at close distances while its other senses are used to locate food
at further distances. The eyes of the Rainbow are well designed for
seeing color. They see color in the red to blue wavelengths about
the same as a human. However, in the yellow to green wavelengths the
trout see color much better than we do. Part of the reason for this
enhanced color perception is that the yellow to blue wavelengths of
light travels better in water than in air.
the eyes on the side of the head also gives the Rainbow Trout a different
perspective on the world. This placement of the eyes allows the fish
to see to the front, sides and most of the way behind. The only blind
spots are immediately behind and directly below the fish. Upward and
directly in front, the fish has depth perception or binocular vision
as both eyes come into play. Toward the rear and to either side, only
the eye on that side is used and the trout has monocular vision without
depth perception. Viewed from below, the water surface reflects light
when viewed at an angle. So the trout can only see the upper world
through a small round 'window' that is directly above and has a diameter
that is about twice the depth of the fish. A trout cruising 10 feet
down can only 'see' a dry fly presented within about 20 feet of its
location. Ears? No, the Rainbow doesn't have an external ear yet it
can hear sound better than almost all land animals. The trout's three-chambered
'internal' ear picks up sound very well. If you drop your glasses
in the bottom of the boat, a trout across a large lake will easily
hear that sound and the nearby trout will probably be spooked into
a non-feeding phase by the noise. The ear also serves as an organ
for balance. Land animals use fluid in the ear for balance. In a fluid
environment, the trout uses calcified stone in each ear chamber to
help it tell up from down and left from right.
of taste and smell are particularly well developed in the Rainbow
Trout. They are better developed than the legendary Bloodhound and
about 500 times more sensitive than these senses in a human. It is
believed that Rainbow Trout, steelhead and salmon (all of the scientific
Order of Oncorhynchus) use taste and smell to help locate the waters
of their original spawning streams.
Trout can smell the difference between two aquatic plants of the same
species that are side by side. It can even taste the difference between
two species of Chironomid and thus will have a preference for one
species over another. Rainbow Trout are very sensitive to differences
in ph, salinity and the differences in amino acids as found in their
food sources. It is thought that the Rainbow may even have taste and
smell sensors on parts of its body other than in the nostrils and
mouth and that these may actually help the trout in locating its food.
you believe that we have yet to come to the most astounding aspect
of the trout's senses? Besides the normal touch sense that most animals
have, the Rainbow Trout has what scientists are calling the "Distant
Touch" sense. This is sort of like Extra-Sensory Perception or ESP.
The scientists aren't exactly sure how this all works but here are
a few of the known details.
is 800 times denser than air. In part, this is why the trout can hear,
smell, taste and see color so well. As a denser medium, water carries
the mechanisms for sensory input much better than air. The senses
of touch and perception are no different. The Rainbow can feel and
perceive distant objects or movements about 800 time's better than
we can and may even have a form of echolocation.
that someone drops a ball of cheese at the other end of a football
field. Other than the fact that you saw it drop, you probably wouldn't
know that it had happened. At that distance, with its eyesight, a
Rainbow Trout wouldn't see the cheese ball drop. However, underwater
it could 'feel' the concussion of the cheese ball hitting the ground,
hear the sound it makes when it hits and may even be able to smell
and taste the cheese shortly after the hard outer cover breaks. It
is even possible that, through echolocation, the trout could tell
us exactly where the cheese ball hits in the end zone.
capable of doing the same would be considered to have ESP. The trout's
primary receptor for this ability is the Lateral Line. It is also
known that the Supra-Orbital and Sub-Orbital lines on the jaw and
back on the trout's skull play a similar role. The trout may have
other distant touch receptors of which we are yet unaware. The full
sensory capabilities of the Rainbow are yet to be determined by the
its distant touch sense, a Rainbow can detect the slightest movement
of an aquatic bug (or fly) at quite a distance and even on the darkest
of nights. It can just as easily detect if the movement is wrong.
For the fly fisher, the reward comes when the trout 'inhales' the
fly very softly. That's a sure indication that the trout is feeding
on the fly rather than taking it out of aggression or territorial
protection. They will 'strike' a fly, sometimes very hard, for a number
of reasons but they will only 'inhale' the fly when they are confident
that it is their desired food source.
equivalents, we seem to have an animal that is faster than a speeding
bullet, able to leap tall buildings in a single bound, is stronger
than a charging locomotive and even has its own form of X-Ray vision
or an equivalent there-of. Remind you of anyone? I'm not sure about
you but I consider the Rainbow Trout to be the Superman of the animal
kingdom. If we were handing out awards, I would certainly vote for
Mother Nature and her creation of the Rainbow Trout.
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