Fishing Articles
Anadromous Ears
Fish have three ears and they know how to
use them to avoid predation
and to find food sources without the need of "sight"
Timothy Kusherets
There are Salmon holding up near some structure on the opposite
shore, right bank. The wake my legs are creating has alerted them, but
because I’ve used unique wading practices, these fish are still
on the bite. The Lamiglas noodle rod is a ten-and-a-half footer; long
enough to get across the river and keep most of the line above the surface
keeping it tight and sensitive to even the most subtle strike.
If how humans and animals hear sound makes up that part of the body
we call ears then anadromous species of fish have three ears and they
know how to use them. I’ve never been convinced that the recreational
fishing world and the scientific community have ever given the credence
to sound that all inland migrating fish experience. Sound travels many
times faster and farther in water than it does in air; effectively giving
all fish a distinct advantage of being able to hear things even when
rivers, lakes, streams, and estuaries have zero visibility. Knowing
how they hear is the right step in the right direction into hooking
into fish; moreover, if anglers know how they hear then they will be
able to avoid spooking fish. Fish, in general, have three physical ways
for hearing sound: the Lateral Line; the Otolith; and facial pores called
Forward Lateral Pores, together they are the Lateral Line System, but
for the purpose of this article we’re going to break them down
into three fundamental groups. All three of these “organs”
(the Otolith is actually a bone surrounded by tissue, but for ease I’ll
refer to it as an organ) are used by fish to perceive water displacement,
which involves current speed, boating, and wading; ironically, these
are very important things to fishermen as well for very different reasons.
The first step in understanding how fish hear is to briefly explore
the Lateral Line.
With the animation of the green dots you can see just how long the Lateral
Line on this fish is. The slightest movement in the water can be detected
though subsonic vibrations. Fish can actually differentiate wave current
motion from that of a fisherman’s foot steps, from a boat, from
a pier, from a predator, and that of prey and they don't need to "see"
any of them. Moving a rock or trodding through the river is a sure way
to put fish off the bite regardless of the clarity of the river, lake,
tributary, estuary, cove, bay, or lake.
Note:
In some species of fish the lateral line passes over the Peduncle and
to the end of the tail.
The Lateral Line is a porous organ that is found on both sides of any
fish’s body that form a canal beneath the skin and scales which
send information, via vibrating hairs at varying depths of the canal,
to the brain and “Otolith. The Lateral Line is a sensory organ
that allows fish to feel vibrations and to sense barometric pressure
changes through vibrations. The ability to sense vibrations works in
conjunction with another organ at the head of fish called the Otolith
(located in a cross sectional above both eye orbits) found deep in the
skull near the brain. The Otolith will actually vibrate much the same
way our ears do when vibrations are sensed; both of these organs work
together to give fish the ability to not only sense vibrations from
predatory fish, but also from prey (an essential tool for those who
want to use live bait). Both organs receive subsonic wave vibrations
that trigger a response of flight or feed. How sound travels and the
anatomical makeup of fish make it vital that fishermen learn how to
wade upstream if they want to keep fish on the bite.
The facial pores of this fish aid it in detecting movement and
sound; after a fashion. Even if fish cannot see you because of turbid
conditions they’ll still be able to hear you and sense vibrations.
Currents that flow over logs and against banks alert fish into avoiding
the structure, if they can do that then avoiding boats and fishermen
is that much easier. Depending on the species of fish will dictate the
size and specific locations of the Forward Lateral System referred to
as facial pores.
Wading upstream from any fish is an advantage as opposed to wading downstream.
From downstream, heading upstream, anglers can actually transmit sound
with little effect on fish because of the diminished surface for receiving
sound. Most fish don’t have any form of sound receptors in the
tail; and experienced anglers will tell you that it’s also their
blind side. If they cannot hear or see you then you can actually sneak
up on them and being able to do that means more fish on the hook. Before
you can sneak up on them we must first discuss the Facial Pores and
then why wading downstream is a no-no. Sheryl Coombs and Christopher
B. Braun have written about these premises in the book Sensory Processing
in Aquatic Environments but have never taken the time to translate the
data into what it could mean for fishermen either commercial or recreational
but the information is vital to understanding the physiology of fish
and what I means for downstream wading anglers.
There are canal lines and pits within the face of each fish a.k.a. Facial
Pores. The pits are extremely sensitive to movement as well as stationary
objects; translation, they can sense the difference between a boat that
drifts, pier that is stationary, and a fisherman wading. Throughout
the head is a map of pores that follow the orbits of the eyes down towards
the maxillary (upper jaw) and the mandible (lower jaw). Generally speaking,
each species of fish will vary slightly, but only slightly so it’s
important to know that if it’s a fish then it has these pores.
There are more pores in the head and the face of fish then throughout
the entire lateral portion of the head, with few exceptions; has an
armada of pores pointed at an angler upstream means fish will be aware
of you long before you’re aware of it. Fishermen have literally
no chance of heading fish off at the pass from a head-on-approach “I’m
not talking about fishing from your position to downstream, which is
done relatively slow, I’m talking about wading downstream to get
to your favorite fishing hole; they’re not the same thing”.
There is a way to circumvent those pores however. When fishing upstream
take the time to actually wade back from your location and head away
from the river, stream, or lake before heading downstream. As you make
your way back to the water be aware that moving upstream will give you
a decided advantage of staying hidden, and with the right offering ensure
that you’ll keep fish on the bite regardless of the species you’re
fishing for; with all of this in mind it’s time to consider how
boats interact with the lateral pores of fish.
Due to all the pores of the Lateral System of fish movement of any kind
can be detected by them no matter how turbid the water is. Boats that
drift or are stationary will actually draw the attention of fish since
they can actually sense the void of waves created by a boat. This void
reveals, to fish, that it offers some kind of cover and fish will head
for it; however, the second a sound comes from the void fish will know
that a predator is waiting to ambush it and will avoid it. Boaters can
counter any chance of making sounds by lining the boat with carpet and
ensuring that when anchoring the rope or chain is off and away from
the hull. The proof is in the pudding; any boater worth his salt has
performed a figure-eight before taking his lure, or bait, out of the
water because he knows that the chances of a fish being under his boat
is real; if proper care is taken it will happen a lot and believe me
you want it to. Not all sound has to be avoided; jus the ones that can
be transmitted into the water, talking, eating, drinking, and fishing
are activities that will not put fish off the bite. The most destructive
activity an angler can perform is to aggressively wade in any body of
water; smooth motions with the current ensure that your motions will
be disguised. I’ve seen it time and again; anglers anxious to
wade out to their favorite fishing spot will move with gusto and in
doing so draw the attention of fish; this is the same as any fisherman
in a sled who roars upstream to until he or she gets to their favorite
hidey-hole. When the fisherman finally gets to the water and casts out
he almost always gets nothing, especially if the cast is short. Military
men call this “hurry up and wait”, and fishermen go through
that enough without perpetrating this annoyance upon themselves by the
way they move upstream. The single best way to wade is with rhythm.
Rhythm wading can be done regardless of how intense the river is flowing
or how low or high it is. It’s all based on the direction of which
you wade; ironically, the wakes waders leave are not necessarily important
on how large the wake is. Wading upstream behind fish will create larger
wakes but will actually disturb fish less than if anglers decide to
aggressively wade downstream. So long as a fisherman wades upstream
with methodical motions fish will not care; you could actually sneak
up behind fish if enough care is taken; I’ve done it quite a few
times. Rhythm wading is done by not trying to walk through the current
above the surface, but rather, wade with your feet below the surface
feeling for rocks and surface areas that offer stability. The stride
of the wades is half that of what you might use downstream. If the wake
in front of the wader becomes sporadic then the stride of the fisherman
has become sporadic and will get the attention of fish. It all comes
to bear on the way fish swim with the current and how it flows over
fish and the direction the Lateral System is aimed at. All fish are
aquatically dynamic in their anatomical makeup, which is partially the
reason why they’re able to differentiate various currents sounds.
If you’re scratching your head wondering why all of this means
anything at all let’s take one final abbreviated look.
All species of fish have the lateral system and can ascertain modulating
amplitudes of sine waves and determine the direction, size, and speed
of movements. The flatter the surface is the easier it is to detect
prey and predator; conversely, spheres or sphere-like surfaces tend
to be hard to detect suggesting a type of sonar but that sonar is done
in the reverse. Sound waves are transmitted “to” fish not
“from” fish and any movement in water is detected by fish
no matter how fast, slow, high, or low the water is.
Remember, if a body part is capable of receiving sounds and that body
part is recognized to be a functioning ear then fish have three of them
and they are the Lateral Line, Otolith, and the Lateral System on the
face and head called Facial Pores. These three things allow fish to
sense you the second you step on the water or the second you make a
sound that transmits from the bottom of the boat into the water. Understanding
current speed, boating, and wading can help you to get fish. You’ll
actually be able to get up behind them undetected or draw them to you
while out boating. What could be better than that?
Further Reading:
Collin, Shaun P., and Marshall, N. Justin. Sensory Processing in an
Aquatic Environment: Processing of Dipole and More Complex Hydrodynamic
Stimuli Under Still-and running-Water Conditions. Springer-Verlag, 2003
Levinton, Jeffery. S. Marine Biology: Physiological and Behavioral Response.
New York: Oxford University Press, 2001.
Baker, Cindy., Carlton, Guy., Diebel, Carol., Montgomery, John., and
Voigt, Rainer. Sensory Processing of Water Currents by Fishes. School
of Biological Sciences, University of Auckland, Private Bag 92019, Auckland,
New Zealand. 2000
© Timothy Kusherets, 2004/09 |
