Another line color question...
R Dean
the length of the leader, i.e., with the vision cone, if the trout was 3 feet
deep, and the leader was 6 feet long, the trout couldn't see it, right? It
would seem improper fly movement is much more important than what the trout
can't see. It would also seem to be more important what the caster can see than
the trout can't.
TIA,
R
Mike Connor
flying through the air, even deep lying trout may be disturbed.
TL
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
""R Dean"" <rde...@flash.netREMOVE> wrote in message
news:38bd4717....@news.flash.net...
ET1
R Dean <rde...@flash.netREMOVE> wrote:
>How could line color matter unless the trout was, basically, at least as deep as
>the length of the leader, i.e., with the vision cone, if the trout was 3 feet
>deep, and the leader was 6 feet long, the trout couldn't see it, right?
The vision cone only occurs when viewing objects in the air from
underwater. Since the line is sitting on the water or is sinking
under the water, the fish should have no trouble seeing it. That
said, I personally don't think line color matter all that much.
Fish are used to seeing all sorts of strange things go floating
by on the water.
- Ken
--
"I went to the woods to live deliberately, to front only the essential facts
of life, and see if I could not learn what it had to teach, and not, when
I came to die, discover that I had not lived." - Henry David Thoreau
R Dean
wrote:
>This only applies when the line is lying on or in the water. When it is
>flying through the air, even deep lying trout may be disturbed.
>
>TL
>MC
Thanks, Mike, but how? With the refraction, distances, etc., how would the
trout be able to even truly "see" any line, especially one in motion, at an
angle, above the water. I understand them seeing large objects, like people,
that appear to "float" in the portion above the 10 degree angle, but just have
to wonder about lines. And again, I understand they might perceive motion, but
motion sensing wouldn't be eliminated by line color, and if it's the motion
sensing causing the disturbance, line color is not the main issue.
TIA
R
R Dean
>In article <38bd4717....@news.flash.net>,
>R Dean <rde...@flash.netREMOVE> wrote:
>>How could line color matter unless the trout was, basically, at least as deep as
>>the length of the leader, i.e., with the vision cone, if the trout was 3 feet
>>deep, and the leader was 6 feet long, the trout couldn't see it, right?
>
>The vision cone only occurs when viewing objects in the air from
>underwater. Since the line is sitting on the water or is sinking
>under the water, the fish should have no trouble seeing it. That
>said, I personally don't think line color matter all that much.
>Fish are used to seeing all sorts of strange things go floating
>by on the water.
>
> - Ken
>
Er, I don't think so, Ken. I'm pretty sure the cone occurs both underwater and
in air, but refraction modifies it above the surface so that the fish can't see
the surface (and a 10 degree angle above it) out and away from the point at
which the cone intersects the surface. That is why I contend line color CAN'T
matter on the surface, at least, if the trout is basically deeper than the
leader is long.
Thanks!
R
ET1
R Dean <rde...@flash.netREMOVE> wrote:
>On 1 Mar 2000 17:08:10 GMT, jan...@pal.ECE.ORST.EDU (ET1) wrote:
>
>>In article <38bd4717....@news.flash.net>,
>>R Dean <rde...@flash.netREMOVE> wrote:
>>>How could line color matter unless the trout was, basically, at least as deep as
>>>the length of the leader, i.e., with the vision cone, if the trout was 3 feet
>>>deep, and the leader was 6 feet long, the trout couldn't see it, right?
>>
>>The vision cone only occurs when viewing objects in the air from
>>underwater. Since the line is sitting on the water or is sinking
>>under the water, the fish should have no trouble seeing it. That
>>said, I personally don't think line color matter all that much.
>>Fish are used to seeing all sorts of strange things go floating
>>by on the water.
>
>in air, but refraction modifies it above the surface so that the fish can't see
>the surface (and a 10 degree angle above it) out and away from the point at
>which the cone intersects the surface. That is why I contend line color CAN'T
>matter on the surface, at least, if the trout is basically deeper than the
>leader is long.
Don't want to get in a pissing match, but if I remember correctly,
the "vision cone" is caused by difference in refraction on the
air/water interface. When looking through that interface the
image is distorted. When looking solely through the air, the
image is not distorted. When looking solely through the water,
the image is not distorted. Therefore I'll agree that the
problem of the fish seeing your line as it sails through the
air is probably minimal, but the fish should have no problem
seeing the line in the water or on the surface of the water.
Someone better at physics than me will have to decide who has
the facts right on this one. I'm done.
rb608
"R Dean" <rde...@flash.netREMOVE> wrote in message
> >
> Er, I don't think so, Ken. I'm pretty sure the cone occurs both
underwater and
> in air, but refraction modifies it above the surface so that the fish
can't see
> the surface (and a 10 degree angle above it) out and away from the point
at
> which the cone intersects the surface. That is why I contend line color
CAN'T
> matter on the surface, at least, if the trout is basically deeper than the
> leader is long.
Boy, I'm sure no expert on fish physiology, but I think your concept of this
"vision cone" thing may be just a bit off. As I understand it, that term
and others like it refer to the trout's ability to see objects above the
surface. This ability is limited optically by the refraction at the
air/water interface; and these limits can be theoretically described as an
inverted cone with its apex at the trout's eye. A handy concept if you're
stalking a wary fish.
In the water, though, a trout can see just fine in all directions. It can
see up for floating insects, down for nymphs, and sideways to see your wader
boots. If your line is in the water, a trout can see it, cone or no cone,
regardless of leader length or depth.
Joe F.
R Dean
>>>>the length of the leader, i.e., with the vision cone, if the trout was 3 feet
>>>>deep, and the leader was 6 feet long, the trout couldn't see it, right?
>>>
>>>The vision cone only occurs when viewing objects in the air from
>>>underwater. Since the line is sitting on the water or is sinking
>>>under the water, the fish should have no trouble seeing it. That
>>>said, I personally don't think line color matter all that much.
>>>Fish are used to seeing all sorts of strange things go floating
>>>by on the water.
>>
>>in air, but refraction modifies it above the surface so that the fish can't see
>>the surface (and a 10 degree angle above it) out and away from the point at
>>which the cone intersects the surface. That is why I contend line color CAN'T
>>matter on the surface, at least, if the trout is basically deeper than the
>>leader is long.
>
>the "vision cone" is caused by difference in refraction on the
>air/water interface. When looking through that interface the
>image is distorted. When looking solely through the air, the
>image is not distorted. When looking solely through the water,
>the image is not distorted. Therefore I'll agree that the
>problem of the fish seeing your line as it sails through the
>air is probably minimal, but the fish should have no problem
>seeing the line in the water or on the surface of the water.
>
you, understand "cone of vision" is that there is a cone (IIRC, about 45 degrees
from each side of vertical, hence the leader/depth correlation) from the fish's
eye in which it can see everything it that cone:
_______ <------surface
\ /
\ /
\ /
O <---- eye of fish
However, when the "cone" intersects the surface, it then becomes a wider angle
(IIRC, about 160 degrees) but not such that the fish can see anything on the
surface beyond the intersection point, therefore, it could not see anything on
the surface past this intersection point that didn't rise, like a fisherman,
into the wider cone, and even then, it would appear to "float" as it could not
see where it contacted the surface outside the cone and was outside the cone
below the surface.
R
R Dean
wrote:
>"R Dean" <rde...@flash.netREMOVE> wrote in message
>news:38bd51ca....@news.flash.net...
>> >
>> Er, I don't think so, Ken. I'm pretty sure the cone occurs both
>underwater and
>> in air, but refraction modifies it above the surface so that the fish
>can't see
>> the surface (and a 10 degree angle above it) out and away from the point
>at
>> which the cone intersects the surface. That is why I contend line color
>CAN'T
>> matter on the surface, at least, if the trout is basically deeper than the
>> leader is long.
>
>Boy, I'm sure no expert on fish physiology, but I think your concept of this
>"vision cone" thing may be just a bit off. As I understand it, that term
>and others like it refer to the trout's ability to see objects above the
>surface. This ability is limited optically by the refraction at the
>air/water interface; and these limits can be theoretically described as an
>inverted cone with its apex at the trout's eye. A handy concept if you're
>stalking a wary fish.
>
>In the water, though, a trout can see just fine in all directions. It can
>see up for floating insects, down for nymphs, and sideways to see your wader
>boots. If your line is in the water, a trout can see it, cone or no cone,
>regardless of leader length or depth.
Well, within their field of vision, yes, so perhaps a better term would be
"conical field of vision" in the water. BTW, IIRC, it is about 45 degrees from
vertical below surface and 160 above. If your line was in the water, and the
fish was facing in its general direction, and the line was within its ability,
distance-wise, it could see it. That would seem to be a placement or technique
question, however, not a color question, IMO.
R
>
>Joe F.
>
>
Rusty Hook
> ....Therefore I'll agree that the
> problem of the fish seeing your line as it sails through the
> air is probably minimal, but the fish should have no problem
> seeing the line in the water or on the surface of the water.
They can and do react to a flyline sailing through the air. I've seen
it myself, while fishing in the high country, and researchers observing
trout underwater have seen it too.
When it's happened to me (at least when I was able to see it for
myself!), I was fishing small streams and/or beaver ponds with clear,
slow water and wary trout. It's probably less of a factor with swifter
currents, lower visibility, etc, but I'd bet that even then, it still
has an effect, especially with larger trout.
--
Rusty Hook
Laramie, Wyo
c...@uwyo.edu
Sent via Deja.com http://www.deja.com/
Before you buy.
ET1
Rusty Hook <trout...@my-deja.com> wrote:
>Ken wrote:
>
>> ....Therefore I'll agree that the
>> problem of the fish seeing your line as it sails through the
>> air is probably minimal, but the fish should have no problem
>> seeing the line in the water or on the surface of the water.
>
>They can and do react to a flyline sailing through the air. I've seen
>it myself, while fishing in the high country, and researchers observing
>trout underwater have seen it too.
>When it's happened to me (at least when I was able to see it for
>myself!), I was fishing small streams and/or beaver ponds with clear,
>slow water and wary trout. It's probably less of a factor with swifter
>currents, lower visibility, etc, but I'd bet that even then, it still
>has an effect, especially with larger trout.
I'm certain it has an effect, I just don't believe it has much of
an effect. Go to your local swimming pool. Put on a pair of
goggles and look up into the air. Even with a mostly still
surface there is a lot of distortion. With even a moderate
water flow and factors like wind disturbance, ripples, etc, I have
doubts about how easy it would be to see something as small as a
fly line in the air above the water. In the water is a whole 'nother
story.
Just my $0.02,
R Dean
>On Wed, 01 Mar 2000 18:04:21 GMT it appears that "R Dean" wrote:
>
>: _______ <------surface
>: \ /
>: \ /
>: \ /
>: O <---- eye of fish
>
>Nah, R., you're way off. The reason those pictures are drawn is to
>show you what makes it *through* the surface. The only reason they
>extend the cone underwater is to picture for you how the above-surface
>rays make it to the fish.
Um, no, they are related, which leads to....
>
>Underwater, a fish has near-360 or maybe full 360 vision. Like many
>animals with eyes on the side of its head, most of this is
>monocular vision, with a narrow area in front (and probably above,
>and possibly behind) that is binocular. I don't have a reference,
>but I would presume they have a blind spot directly below, but they
>certainly can see everything above.
....they most certainly do not have 360 degree vision. And IIRC, they have an
area of about 40 degrees of forward "binocular vision range."
>
>If you were underwater, it'd be just like the rule of thumb for
>not sneaking up on a horse (to avoid a fear-kick reaction) -- if
>you can see his eye, he can see you.
Er, I'm not sure what you mean here, but a person with goggles is not the same
as fish's eye, it just makes the light rays, "vision," seem to have SOME
similarity. And horses don't behave like that. As to seeing the eye, that is
not accurate.
Thanks anyway,
R
>
>JonCook.
R Dean
I'll respond to both, as they are related. Seeing or sensing motion isn't
color, but I'll agree they could correlate. I would suggest that unless they
correlate the movement with the "fake food" and being caught, they aren't going
to care what color something unrelated thing is. If any movement made them more
wary than normal, they would never eat, as there is always movement in nature.
It is a cause and effect thing. If you're really worried, false cast over a
pool for a while before actually "fishing."
BTW, goggles won't give you true "fish vision"...
Mine, "2"...
R
CodeMarine
news:89jqhc$l26$1...@news.NERO.NET...
> I have doubts about how easy it would be to see something as small
> as a fly line in the air above the water. In the water is a whole 'nother
> story.
>
Hmm... Well, the fish at my favorite pond sure are seeing *something* when I
cast over the top of them, because they scatter. From 30', I cannot see them
and I doubt they can see me, but if I cast over the top of them, these fish
will bolt. How do I know they bolt if I cannot see them? Because they often
feed so close to the surface of the water that I can see the wake. Something
I'm doing scares them, no doubt about it. And the bolt occurs while the line
is still in the air.
Perhaps it's droplets of water from the line or the nylon loop connector?
--Steve
Kevin Vang
ET1 wrote:
>
> R Dean <rde...@flash.netREMOVE> wrote:
>
> >>The vision cone only occurs when viewing objects in the air from
> >>underwater.
>
> >Er, I don't think so, Ken. I'm pretty sure the cone occurs both underwater and
> >in air, but refraction modifies it above the surface so that the fish can't see
> >the surface (
>
> Don't want to get in a pissing match, but if I remember correctly,
> the "vision cone" is caused by difference in refraction on the
> air/water interface. When looking through that interface the
> image is distorted. When looking solely through the air, the
> image is not distorted. When looking solely through the water,
> the image is not distorted. Therefore I'll agree that the
> problem of the fish seeing your line as it sails through the
> air is probably minimal, but the fish should have no problem
> seeing the line in the water or on the surface of the water.
>
The "vision cone" does in fact only apply to looking at objects
in the air from the water. The ideas is this: When a ray of light
hits the water at an angle of less than x degrees (where x is close
to 45, but I am too lazy to go look it up) from the vertical, it will
pass through the surface (getting refracted (bent) along the way.)
If it strikes the surface at an angle of greater than x degrees, it is
reflected. Thus, if you are a fish looking up, inside the "vision
cone" what you see is made up of light rays that have come from
outside the waters surface, while outside the cone you see is made
up of light rays that have originated under the waters surface and
have been reflected back downward.
You can see this for yourself the next time you go swimming. If
you drop to the bottom of the pool and look up, you will see a
circle directly above you where you see objects from above the
surface, and outside that circle you see a mirror image of the
bottom. If you are looking at objects which are underwater, you
can see in any direction. At least that is what you would see if the
surface was flat calm -- if there are waves on the surface or there
is a hundred screaming 7 year olds in the pool with you, then its hard to
make out much of anything above the surface, which I think explains
why the fishing is best below the surface on windy days, and
fishing on the surface works best on calm days.
As far as line color goes, I would have to say that sometimes it
matters, but most of the time it seems to not make much difference.
Fish are very skittish about movement above the surface (the main
threat to their life comes from kingfishers, herons, ospreys, etc)
so keep your self, your rod, and your loops as low as possible
and hope for the best.
Kevin
ET1
R Dean <rde...@flash.netREMOVE> wrote:
>On 1 Mar 2000 19:01:54 GMT, Jonathan Cook <jc...@cs.nmsu.edu> wrote:
>
>>Underwater, a fish has near-360 or maybe full 360 vision. Like many
>>animals with eyes on the side of its head, most of this is
>>monocular vision, with a narrow area in front (and probably above,
>>and possibly behind) that is binocular. I don't have a reference,
>>but I would presume they have a blind spot directly below, but they
>>certainly can see everything above.
>
>....they most certainly do not have 360 degree vision. And IIRC, they have an
>area of about 40 degrees of forward "binocular vision range."
Just a clarification: Jon said they have near 360 degree MOSTLY
MONOCULAR vision. You said that they have about 40 degrees of
BINOCULAR vision. The two do not necessarily contradict each
other.
You seem to be under the impression that fish see as we do.
That the only thing they can see is in the region overlapped
by both eyes. It is my understanding that, as with most
animals with the eyes on the side of their heads, each eye is
able to function more or less independently and they can see
almost 360 degrees, but with accurate depth perception only
in the overlapping region.
Again, just my $0.02,
Rusty Hook
> >Ken wrote:
> I'm certain it has an effect, I just don't believe it has much of
> an effect. Go to your local swimming pool. Put on a pair of
> goggles and look up into the air. Even with a mostly still
> surface there is a lot of distortion. With even a moderate
> doubts about how easy it would be to see something as small as a
> fly line in the air above the water. In the water is a whole 'nother
> story.
Borger talks about that in "Presentation".
It's a big part of why riffles can be easier to fish than slick water,
once you get the currents figured out.
Granted that turbulent water make *anything* on or especially above the
surface harder to see from below, I'd still choose a dull green flyline
over a bright orange one, assuming the green is available.
OTOH, it's not a big enough deal that I'd throw out a perfectly good
line because it's the "wrong" color. It's just one of those little
things that can add up.
R Dean
wrote:
>ET1 <jan...@pal.ECE.ORST.EDU> wrote in message
>news:89jqhc$l26$1...@news.NERO.NET...
>> I have doubts about how easy it would be to see something as small
>> as a fly line in the air above the water. In the water is a whole 'nother
>> story.
>>
>
>Hmm... Well, the fish at my favorite pond sure are seeing *something* when I
>cast over the top of them, because they scatter. From 30', I cannot see them
>and I doubt they can see me, but if I cast over the top of them, these fish
>will bolt. How do I know they bolt if I cannot see them? Because they often
>feed so close to the surface of the water that I can see the wake. Something
>I'm doing scares them, no doubt about it. And the bolt occurs while the line
>is still in the air.
They may see a lot of things, and it could be them seeing you, the rod motion,
etc. Could/would you describe more fully, i.e., wading or from bank, depth of
fish and pond, current, water clarity, etc. One thing, and I'm not trying to
be a wiseass, but if you can't see them, how did you know they bolted? From
surface movement?
>
>Perhaps it's droplets of water from the line or the nylon loop connector?
<snicker>
R
>
>--Steve
>
>
Charlie Choc
>Perhaps it's droplets of water from the line or the nylon loop connector?
>
Shock wave from the supersonic rod tip.
--
Charlie...
Ken Fortenberry
>
> "CodeMarine" wrote:
>
> >Perhaps it's droplets of water from the line or the nylon loop connector?
> >
> Shock wave from the supersonic rod tip.
A heads up from the psychic hot line.
--
Ken Fortenberry
ke...@uiuc.edu
R Dean
>In article <38bd6e07....@news.flash.net>,
>R Dean <rde...@flash.netREMOVE> wrote:
>>On 1 Mar 2000 19:01:54 GMT, Jonathan Cook <jc...@cs.nmsu.edu> wrote:
>>
>>>Underwater, a fish has near-360 or maybe full 360 vision. Like many
>>>animals with eyes on the side of its head, most of this is
>>>monocular vision, with a narrow area in front (and probably above,
>>>and possibly behind) that is binocular. I don't have a reference,
>>>but I would presume they have a blind spot directly below, but they
>>>certainly can see everything above.
>>
>>....they most certainly do not have 360 degree vision. And IIRC, they have an
>>area of about 40 degrees of forward "binocular vision range."
>
>Just a clarification: Jon said they have near 360 degree MOSTLY
>MONOCULAR vision. You said that they have about 40 degrees of
>BINOCULAR vision. The two do not necessarily contradict each
>other.
Well, not exactly, and I said FORWARD monocular, and it's an important
distinction. And they do not have 360 vision, binocular or monocular, IIRC.
>
>You seem to be under the impression that fish see as we do.
>That the only thing they can see is in the region overlapped
>by both eyes. It is my understanding that, as with most
>animals with the eyes on the side of their heads, each eye is
>able to function more or less independently and they can see
>almost 360 degrees, but with accurate depth perception only
>in the overlapping region.
Not at all. The eyes are different, but the light behaves the same. When I
have time, I have some reference material I'll refer to and report on.
>
>Again, just my $0.02,
> - Ken
Thanks again, and same here, at this point...
R
>
William Loehman/Susan Schwarz
I think that factors such as line color and line weight do matter but
part of the time. If you're fishing a turbulent deep run with off color
water, line weight or color is not going to have much effect even if you
line a fish. However, in shallow, clear, calm water situations both line
weight and color can matter. Fish feeding in those situations can even
be scared off by slight drag on a fly.
I'm not sure the vision cone argument matters. Even with a long leader,
you are likely to be lining fish. Even though you may not be lining your
target fish, chances are your line will be passing over other fish that
won't be visible to you. If you spook them, you chance spooking the fish
that you're targeting.
George's comment about seeing a fish's fin twitch letting you know that
it's aware of your presence is a good one. I think that fish can go
through a series of reactions to an angler's presence before they get
totally spooked or stop feeding. The less a fish is aware of your or a
presence, the more likely you are to be successful.
Take a surface feeding fish as an example. With a stealthy approach and
a good presentation, success on your first cast is very likely even if
your fly is not "perfect." It is the highest percentage cast. If the
fish notices something amiss on your presentation, it is likely to get
more discriminating and more difficult to take. A "better" fly or finer
tippet may be needed. A few bad casts or dragging flies will often put
the fish off of feeding on the surface, although it may continue to feed
underwater at the same feeding station. More mistakes and the fish may
move and set a feeding station in another location. Too much disturbance
and the fish will be totally spooked and stop feeding. Trout in
extremely heavily fished waters are an exception to the above.
Willi
gol...@frii.com
Charlie Choc
>With even a moderate
>water flow and factors like wind disturbance, ripples, etc, I have
>doubts about how easy it would be to see something as small as a
>fly line in the air above the water. In the water is a whole 'nother
>story.
I expect the shadow would have more effect than the color both above
and below the water anyway.
--
Charlie...
R Dean
>ET1 wrote:
>>
>> R Dean <rde...@flash.netREMOVE> wrote:
>>
>> >>The vision cone only occurs when viewing objects in the air from
>> >>underwater.
>
>>
>> >Er, I don't think so, Ken. I'm pretty sure the cone occurs both underwater and
>> >in air, but refraction modifies it above the surface so that the fish can't see
>> >the surface ( __RESTORED SNIP___and a 10 degree angle above it) out and away from the point at
>which the cone intersects the surface.
If you are going to edit, please don't do so as to change meanings...Ken didn't
edit it, you did....
>>
>> Don't want to get in a pissing match, but if I remember correctly,
>> the "vision cone" is caused by difference in refraction on the
>> air/water interface. When looking through that interface the
>> image is distorted. When looking solely through the air, the
>> image is not distorted. When looking solely through the water,
>> the image is not distorted. Therefore I'll agree that the
>> problem of the fish seeing your line as it sails through the
>> air is probably minimal, but the fish should have no problem
>> seeing the line in the water or on the surface of the water.
>>
>
>The "vision cone" does in fact only apply to looking at objects
>in the air from the water.
Er, no, that is the effect, not the application, but perhaps "conical field of
vision" is more descriptive...
>The ideas is this: When a ray of light
>hits the water at an angle of less than x degrees (where x is close
>to 45, but I am too lazy to go look it up) from the vertical, it will
>pass through the surface (getting refracted (bent) along the way.)
>If it strikes the surface at an angle of greater than x degrees, it is
>reflected. Thus, if you are a fish looking up, inside the "vision
>cone" what you see is made up of light rays that have come from
>outside the waters surface, while outside the cone you see is made
>up of light rays that have originated under the waters surface and
>have been reflected back downward.
>
>You can see this for yourself the next time you go swimming.
SNIPPED, because no, you can't, not unless you are a fish.
>
>As far as line color goes, I would have to say that sometimes it
>matters, but most of the time it seems to not make much difference.
>Fish are very skittish about movement above the surface (the main
>threat to their life comes from kingfishers, herons, ospreys, etc)
>so keep your self, your rod, and your loops as low as possible
>and hope for the best.
IMO, excellent, accurate, and critical advice here, and not to pick nits, but
"fish" is a little broad...<G>...
>
>Kevin
>
Thanks,
R
PS, can you turn off the MIME?
V. Ursenbach
mountain stream in Utah. Check out the photos and trip report at
http://msnhomepages.talkcity.com/ResortRd/v_deloy/NEWS1.html
My question is, can fish see directly behind them? If so, what kind of
proof is there to support your claim?
I had previously posted this report on ROFF and some nice advice from
good friends like Mike Connor. Ideas ranged from shadows on the water,
flash of brightly colored line, etc. However, I still wonder if fish
can see directly behind them.
A horse can see almost everything but does have blind spots. A horse's
blind spots are at the very tip of his mouth, underneath him, and
directly behind him. I thought fish would be the same due to their eye
placement.
--
Vern
My ROFF page:
http://msnhomepages.talkcity.com/ResortRd/v_deloy/ROFFintro.html
In article <89jpgl$2d9$1...@nnrp1.deja.com>,
Rusty Hook <trout...@my-deja.com> wrote:
> Ken wrote:
>
> > ....Therefore I'll agree that the
> > problem of the fish seeing your line as it sails through the
> > air is probably minimal, but the fish should have no problem
> > seeing the line in the water or on the surface of the water.
>
> They can and do react to a flyline sailing through the air. I've seen
> it myself, while fishing in the high country, and researchers
observing
> trout underwater have seen it too.
> When it's happened to me (at least when I was able to see it for
> myself!), I was fishing small streams and/or beaver ponds with clear,
> slow water and wary trout. It's probably less of a factor with swifter
> currents, lower visibility, etc, but I'd bet that even then, it still
> has an effect, especially with larger trout.
>
daytripper
>Charlie Choc wrote:
>>
>> "CodeMarine" wrote:
>>
>> >Perhaps it's droplets of water from the line or the nylon loop connector?
>> >
>> Shock wave from the supersonic rod tip.
>
>A heads up from the psychic hot line.
LMAO!
V. Ursenbach
report at http://msnhomepages.talkcity.com/ResortRd/v_deloy/NEWS1.html
and see the photos as well. I would like to know how to fix the
problem.
--
Vern
In article <Vjev4.324$DJ....@news.ipass.net>,
"CodeMarine" <st...@codeDELETETHISmarine.com> wrote:
> ET1 <jan...@pal.ECE.ORST.EDU> wrote in message
> news:89jqhc$l26$1...@news.NERO.NET...
> > I have doubts about how easy it would be to see something as small
> > as a fly line in the air above the water. In the water is a whole
'nother
> > story.
> >
>
> Hmm... Well, the fish at my favorite pond sure are seeing *something*
when I
> cast over the top of them, because they scatter. From 30', I cannot
see them
> and I doubt they can see me, but if I cast over the top of them,
these fish
> will bolt. How do I know they bolt if I cannot see them? Because they
often
> feed so close to the surface of the water that I can see the wake.
Something
> I'm doing scares them, no doubt about it. And the bolt occurs while
the line
> is still in the air.
>
> Perhaps it's droplets of water from the line or the nylon loop
connector?
>
> --Steve
CodeMarine
> They may see a lot of things, and it could be them seeing you, the rod
motion,
> etc. Could/would you describe more fully, i.e., wading or from bank,
depth of
> fish and pond, current, water clarity, etc. One thing, and I'm not
trying to
> be a wiseass, but if you can't see them, how did you know they bolted?
From
> surface movement?
Ok, here are the details. The pond where I fish is man made, with no cover.
The fish (bass, bream) hug the shoreline (ie. from 6 inches to 6 feet from
the bank), in clear water often no deeper than a foot or two. So I walk
along casting almost parallel to the shoreline, probably an average casting
distance of say 25'.
I should point out that there is a walking path that encircles the pond no
more than about 10 feet from the shore, so the fish are used to people and
dogs running by. That doesn't seem to make them bolt. Oh, yeah, and I know
they bolt because they are so close to the surface that I can see the wake.
If I walk along without casting, I can get fairly close to the
fish--probably within 10-15 feet or so. But if I cast over the top of them,
even from a further distance, they bolt. It might be the movement of my arm,
but I suspect it is the line or the shadow thereof directly above them that
sets them off. I'm not the best caster in the world, mind you, but the bolt
does definitely happen *before* the line splashes down into the water.
Perhaps I need to have the Zimmerpond Clave 2000 and let you guys see for
yourself. It's kinda cool walking along and seeing a 6-pound bass sitting
there in about a foot of water waiting for something to "swim" past it.
--Steve
Mike Connor
and scatter in such cases. It is unlikely that they see accurate details of
the birds, even when the water is calm and clear. They see rapid movement
which they instinctively associate with danger. The colour is probably not
quite so important, but light coloured lines do indeed flash more than dull
coloured ones, and the fast movement coupled with this flashing will put
fish down.
I have often caught fish in some pools by simply feeding line out slowly.
Any attempt to cast in these places immediately put all the fish down. This
is most apparent in bright sunny weather. I have also experienced the
"shadow" of a fly-line putting fish down. Once the line is on or under the
water surface the colour is probably immaterial, as the fish has no way of
connecting a piece of coloured line with danger as long as it is not doing
something other than just floating.
There has been a great deal of research into fish vision, and it is very
interesting. However this has little to do with panic reactions caused by
rapid aerial movement. Just wave your rod over any fish for instance, and
it will immediately take off. Moving it relatively slowly over them will not
normally panic them, especially near trees, as presumably they are used to
seeing branches leaves etc moving in the wind, and "know" instictively that
these things are not dangerous. The "flash" from a polished reel or even
from rod varnish will also put fish down. Fish react instinctively to many
stimuli, most of these activate survival mechanisms, which cause the fish to
become more alert, to cease feeding, or to flee. Practically any movement
or vibration to which the fish is not accustomed will cause it to flee. This
is the single most important survival trait for a fish.
I think line colour is important for this reason. Dull coloured lines cause
less flash. I also use matt finished rods and reels and all other equipment
as a matter of course. You can try a simple experiment here. Next time you
go fishing take a small pocket mirror along. Find a position where you can
observe the fish without disturbing them, and "flash" the mirror at them.
They will flee immediately. This works with a shiny rod or other equipment
as well.
TL
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
"CodeMarine" <st...@codeDELETETHISmarine.com> wrote in message
news:Vjev4.324$DJ....@news.ipass.net...
stephen welsh
: And again, I understand they might perceive motion, but
: motion sensing wouldn't be eliminated by line color, and if it's the motion
: sensing causing the disturbance, line color is not the main issue.
Waaay baaack ...
******
>> Forum: rec.outdoors.fishing.fly
>> Thread: Fly Lines - What color?
>> Message 32 of 48
Subject:
Re: Fly Lines - What color?
Date:
06/10/1997
Author:
Stephen Welsh <st...@ip2.cs.monash.edu.au>
wrote (In addition to a post from wayne: trz...@CS.ColoState.EDU)
I tend to agree with Wayne - having tried bright green, gray, blue, brown
and tan - I can honestly say there is no difference once the thing is on the
water at least where I fish. I used to wonder just how visible an aerialised
line is to fish until a few weeks ago on a lake. A cast between two cruising
fish caused them to scatter while the thing was still in the air.
A plane passing caused a similar reaction - it was at about 2000ft in a
dead calm. Its movement that is the problem. I guess camouflaged lines are
harder to detect against a backdrop of trees, mountains etc - but in the open
against a bright sky ....
*************
I think its flash that adds to the movement, go dull ... bright colour but
... minimal specular reflections.
steve
--
"Experience must be the teacher in this game - not only your own
but the other man's" - Dick Wigram
Wayne Harrison
the vast number of weighty pronouncements and speculations which have come
before, but here is my read on the issue, fwiw, in the inimitable words of
le duc du chocolat:
the goddam fish is not going to give a happy rat's ass about the color
of your line. it is the *movement* of the line that he reacts to, not its
color. surely none of us thinks that some brookie is lolling contentedly in
his feeding lane, glances "up", sees an orange colored line, and says to
himself, "well, hell; there's that fool waldo again, trying to fish with an
orvis three weight again; i'll just ignore his silly ass. sure am glad he
isn't using one of those mottled green stealth lines like george (king of
the world) gerkhe!" and anyone who actually thinks that any available color
line will conceal the movement of that line has been spending too much time
on weekends at asadi's house. the answer, of course, is the same for our
halfordian exercise as it is in real golf: keep it low and slow.
wayno
ET1
R Dean <rde...@flash.netREMOVE> wrote:
>On 1 Mar 2000 19:42:25 GMT, jan...@pal.ECE.ORST.EDU (ET1) wrote:
>
>>In article <38bd6e07....@news.flash.net>,
>>R Dean <rde...@flash.netREMOVE> wrote:
>>>On 1 Mar 2000 19:01:54 GMT, Jonathan Cook <jc...@cs.nmsu.edu> wrote:
>>>
>>>>Underwater, a fish has near-360 or maybe full 360 vision. Like many
>>>>animals with eyes on the side of its head, most of this is
>>>>monocular vision, with a narrow area in front (and probably above,
>>>>and possibly behind) that is binocular. I don't have a reference,
>>>>but I would presume they have a blind spot directly below, but they
>>>>certainly can see everything above.
>>>
>>>....they most certainly do not have 360 degree vision. And IIRC, they have an
>>>area of about 40 degrees of forward "binocular vision range."
>>
>>Just a clarification: Jon said they have near 360 degree MOSTLY
>>MONOCULAR vision. You said that they have about 40 degrees of
>>BINOCULAR vision. The two do not necessarily contradict each
>>other.
>
>Well, not exactly, and I said FORWARD monocular, and it's an important
>distinction. And they do not have 360 vision, binocular or monocular, IIRC.
It's impossible to have 360 degree vision due to the distance
between the back to back eyes, but they can have very close to
360 degrees. I've always been under the impression that a fish's
eye sees a very wide angle (close to 180 degrees) and that put
together they can see almost the full 360 degrees. I'm afraid
I need a reference or at least a reasonable argument of why
they cannot see nearly 360 degrees.
R Dean
wrote:
>"R Dean" <rde...@flash.netREMOVE> wrote in message
>news:38bd71b1....@news.flash.net...
>> They may see a lot of things, and it could be them seeing you, the rod
>motion,
>> etc. Could/would you describe more fully, i.e., wading or from bank,
>depth of
>> fish and pond, current, water clarity, etc. One thing, and I'm not
>trying to
>> be a wiseass, but if you can't see them, how did you know they bolted?
>From
>> surface movement?
>
>Ok, here are the details. The pond where I fish is man made, with no cover.
>The fish (bass, bream) hug the shoreline (ie. from 6 inches to 6 feet from
>the bank), in clear water often no deeper than a foot or two. So I walk
>along casting almost parallel to the shoreline, probably an average casting
>distance of say 25'.
>
>I should point out that there is a walking path that encircles the pond no
>more than about 10 feet from the shore, so the fish are used to people and
>dogs running by. That doesn't seem to make them bolt. Oh, yeah, and I know
>they bolt because they are so close to the surface that I can see the wake.
If they can see them, it has probably developed a "no problem" relationship for
them, i.e., they have no reason to fear whatever they perceive, if anything, on
the path.
>If I walk along without casting, I can get fairly close to the
>fish--probably within 10-15 feet or so. But if I cast over the top of them,
>even from a further distance, they bolt. It might be the movement of my arm,
>but I suspect it is the line or the shadow thereof directly above them that
>sets them off. I'm not the best caster in the world, mind you, but the bolt
>does definitely happen *before* the line splashes down into the water.
Remember when you get that close and start "waving" things, they might "see" all
sorts of things. If you care to figure what they might see, the "no see" area
is about upto about a 10 degree angle ABOVE the surface, and figure in the
amount of blockage the curve/angle of the bank plays. The path, I would think,
is not at "pond level" hence the bank factor.
Could you try casting from farther back, say on the path? We have a fairly
large tank (now a small lake, really) with muddy, cattle-tracked banks, so we
cast from about 20 feet from the waterline, or from the dock/pier/swim platform,
and they don't seem to see us...
Mu Young Lee
> I'm pretty sure the cone occurs both underwater and
> in air, but refraction modifies it above the surface so that the fish
> can't see the surface (and a 10 degree angle above it) out and away from
> the point at which the cone intersects the surface.
In Marinaro's "In the ring of the rise" there are photos of dry flies as
viewed from underwater at several angles (distances away from the camera).
It seems quite clear empirically from these photos that any creature with
eyes that can look upward from an underwater position will be able to
detect items floating on a smooth surface regardless of the effects of
total internal reflection. Besides, a fly line doesn't really sit on top
of the surface; part of it breaks the surface. Within its range of sight,
the fish will be able to see any object that is underwater like the bottom
portion of a fly line. Of course, on riffled water it would look totally
different or perhaps even undetectable. The reason a fish cannot see
beyond the 97degree/160degree cone into the atmosphere is due to a
phenomenon called total internal reflection. If you are underwater in a
pool and look straight up at the surface and begin to look away from
vertical, there is an angle beyond which you cannot see through the
surface into the airy world above. That critical angle is approximately
where your line of sight is 43 degrees above the horizontal. If your line
of sight is 43 degrees or less with the horizontal you will see a
reflection of the bottom of the pool mirrored on the underside of the
water surface.
Optics is not taught very thoroughly in many American physics courses. It
seemed to be a traditional weakness among US contestants to the
international high school physics olympiads (at least when I was in
high school).
Mu, product of a New York City public school education
R Dean
>the vast number of weighty pronouncements and speculations which have come
>before, but here is my read on the issue, fwiw, in the inimitable words of
>le duc du chocolat:
Well, if helps, _I_ read it...<G>. Of course, if it truly helps, get out
more.....<G>
>
> the goddam fish is not going to give a happy rat's ass about the color
>of your line. it is the *movement* of the line that he reacts to, not its
>color. surely none of us thinks that some brookie is lolling contentedly in
>his feeding lane, glances "up", sees an orange colored line, and says to
>himself, "well, hell; there's that fool waldo again, trying to fish with an
>orvis three weight again; i'll just ignore his silly ass. sure am glad he
>isn't using one of those mottled green stealth lines like george (king of
>the world) gerkhe!" and anyone who actually thinks that any available color
>line will conceal the movement of that line has been spending too much time
>on weekends at asadi's house. the answer, of course, is the same for our
>halfordian exercise as it is in real golf: keep it low and slow.
Yep, pretty much one way of accurately saying it...
>
>wayno
>
>
Thanks,
R
Kevin Vang
R Dean wrote:
> If you are going to edit, please don't do so as to change meanings...Ken didn't
> edit it, you did....
>
Sorry, I wasn't intending to change meaning or misattribute any quotes.
I just wanted to include only the gist of the previous messages so that my
own post wouldn't be excessively long.
>
>
> >You can see this for yourself the next time you go swimming.
>
> SNIPPED, because no, you can't, not unless you are a fish.
But you can. Honest. Try it.
>
> >As far as line color goes, I would have to say that sometimes it
> >matters, but most of the time it seems to not make much difference.
> >Fish are very skittish about movement above the surface (the main
> >threat to their life comes from kingfishers, herons, ospreys, etc)
> >so keep your self, your rod, and your loops as low as possible
> >and hope for the best.
>
> IMO, excellent, accurate, and critical advice here, and not to pick nits, but
> "fish" is a little broad...<G>...
>
Granted. A 20 pound pike probably doesn't need to be afraid of
much of anything, but if it didn't instinctively flee from movement, it
probably would have never lived long enough to get that big.
>
> Thanks,
> R
>
> PS, can you turn off the MIME?
Um, I'll try. Is this better?
Kevin
V. Ursenbach
source of wonderful information, thanks. However, I would still like
to
know if fish can see directly behind them.
--
Vern
Sent via Deja.com http://www.deja.com/
Before you buy.
R Dean
>R Dean wrote:
>
>> If you are going to edit, please don't do so as to change meanings...Ken didn't
>> edit it, you did....
>
>Sorry, I wasn't intending to change meaning or misattribute any quotes.
>I just wanted to include only the gist of the previous messages so that my
>own post wouldn't be excessively long.
Didn't think you did, but....thanks for your understanding.
>>
>>
>> >You can see this for yourself the next time you go swimming.
>>
>> SNIPPED, because no, you can't, not unless you are a fish.
>
>But you can. Honest. Try it.
Well, I maintain that human eyes are different, and goggles don't make them
equal, whether you meant use them or not, but let's agree to disagree here.
>
>>
>> >As far as line color goes, I would have to say that sometimes it
>> >matters, but most of the time it seems to not make much difference.
>> >Fish are very skittish about movement above the surface (the main
>> >threat to their life comes from kingfishers, herons, ospreys, etc)
>> >so keep your self, your rod, and your loops as low as possible
>> >and hope for the best.
>>
>> IMO, excellent, accurate, and critical advice here, and not to pick nits, but
>> "fish" is a little broad...<G>...
>>
>
>Granted. A 20 pound pike probably doesn't need to be afraid of
>much of anything, but if it didn't instinctively flee from movement, it
>probably would have never lived long enough to get that big.
Um, thanks, I obscured my own meaning. I meant to comment about the threat
regarding "fish."
>>
>> PS, can you turn off the MIME?
>
>Um, I'll try. Is this better?
Still showing MIME..
TC,
R
>Kevin
>
Jon McAnulty
> the goddam fish is not going to give a happy rat's ass about the color
> of your line. it is the *movement* of the line that he reacts to, not its
> color.
No problem with that. You see examples of it in any number of predator-prey
relationships. The outstanding question remains, though, "Does the color of the
line inhibit the fish from perceiving the motion quite as readily- therefore
adding one small incremental advantage to the angler?" If I go turkey hunting in
full camo and move slightly, it is much less likely that I will be sensed
(visual alarm or trigger may be a good concept) than if I am there in very
contrasty colors. The other thing that is not addressed in this august debate is
the effect of sun on the perceived line color. If its real sunny, the underside
will be heavily shaded in comparison to the bright light around it and will
stand out. Maybe white is the only viable color!
Fire at will.
Jon
Wolfgang
ET1 wrote:
> a fish has near-360 or maybe full 360 vision
> >>>....they most certainly do not have 360 degree vision.
> Jon said they have near 360 degree MOSTLY
> >>MONOCULAR vision. You said that they have about 40 degrees of
> >>BINOCULAR vision. The two do not necessarily contradict each
> >>other.
> >
> >Well, not exactly, and I said FORWARD monocular, and it's an important
> >distinction. And they do not have 360 vision, binocular or monocular, IIRC.
>
> It's impossible to have 360 degree vision due to the distance
> between the back to back eyes, but they can have very close to
> 360 degrees. I've always been under the impression that a fish's
> eye sees a very wide angle (close to 180 degrees) and that put
> together they can see almost the full 360 degrees. I'm afraid
> I need a reference or at least a reasonable argument of why
> they cannot see nearly 360 degrees.
Guys. Ever hear of fisheye lenses? Ever wonder why they call them that?
R Dean
Again, substitute, "conical field of vision" for "cone." Otherwise, I agree
with your basic premise, but it assumes a fish has infinite vision over the
infinite surface of an infinite plane in an unobstucted manner. In other words,
in the real world, a fish (or human) can only see as far as its unobstucted
"eyesight" allows _AND_ within its field of vision, neither of which is
infinite. The surface basically only affects the vision, rather than create it.
R
>
>
>
ET1
Right. That's why I'm so confused by the assertion that a fish
can't see nearly 360 degrees. A fisheye lens has a field of view
of 180 degrees (I checked). Since a fish's eyes are on opposite
sides of it's head, it should be able to see nearly 360 degrees.
Paul Meyers
R Dean wrote:
> How could line color matter unless the trout was, basically, at least as deep as
> the length of the leader, i.e., with the vision cone, if the trout was 3 feet
> deep, and the leader was 6 feet long, the trout couldn't see it, right? It
> would seem improper fly movement is much more important than what the trout
> can't see. It would also seem to be more important what the caster can see than
> the trout can't.
>
> TIA,
> R
I don't think that is correct. The cone is the angle that light can escape (enter)
the water (pass from air to water). Otherwise the light reflects. If the line is
on the
water (or in) light no longer has to pass from air to water. Therefore, the
fish should be able to see the line on the water (not above the water.)
Regards,
Paul Meyers
Jon McAnulty
> In article <38BD8746...@post.its.mcw.edu>,
> Wolfgang <wolf...@mcw.edu> wrote:
> >ET1 wrote:
> >> a fish has near-360 or maybe full 360 vision
> >> >>>....they most certainly do not have 360 degree vision.
> >
> >> Jon said they have near 360 degree MOSTLY
> >> >>MONOCULAR vision. You said that they have about 40 degrees of
> >> >>BINOCULAR vision. The two do not necessarily contradict each
> >> >>other.
> >> >
> >> >Well, not exactly, and I said FORWARD monocular, and it's an important
> >> >distinction. And they do not have 360 vision, binocular or monocular, IIRC.
> >>
> >> It's impossible to have 360 degree vision due to the distance
> >> between the back to back eyes, but they can have very close to
> >> 360 degrees. I've always been under the impression that a fish's
> >> eye sees a very wide angle (close to 180 degrees) and that put
> >> together they can see almost the full 360 degrees. I'm afraid
> >> I need a reference or at least a reasonable argument of why
> >> they cannot see nearly 360 degrees.
> >
> >Guys. Ever hear of fisheye lenses? Ever wonder why they call them that?
>
> Right. That's why I'm so confused by the assertion that a fish
> can't see nearly 360 degrees. A fisheye lens has a field of view
> of 180 degrees (I checked). Since a fish's eyes are on opposite
> sides of it's head, it should be able to see nearly 360 degrees.
Right, but if the vision from the two eyes overlaps at all (zone of binocular
vision) then there will be an area where they don't overlap (no vision) unless the
field of vision is greater than 180.
Jon
R Dean
Well, it's my contention that depnding on depth, the fish can't see ANYTHING at
a certain distance, whether at or above the surface, and of course, a different
distance, below the water.
Thanks!
R
ET1
Hence the *NEAR* 360 degrees. Near is a relative term of course.
The general meaning being that a fish can see a good portion
of the world around it at any given time. I've long since forgotten
why this was important, but now curiousity has gotten the better
of me and I just have to know for my own peace of mind. :-)
Anybody know what the field of view of a trout is?
Jon McAnulty
> Hence the *NEAR* 360 degrees. Near is a relative term of course.
> The general meaning being that a fish can see a good portion
> of the world around it at any given time. I've long since forgotten
> why this was important, but now curiousity has gotten the better
> of me and I just have to know for my own peace of mind. :-)
> Anybody know what the field of view of a trout is?
>
Right and it depends on how picky you want to get and how near NEAR really is. If it is
40 degrees then that is a big enough chunk to not be NEAR in my book but your book may
differ. People are quoting a lot of precise numbers so to fall back on NEAR as all
inclusive of any variant is not a particularly compelling argument.
Jon
Charlie Choc
Wild, native, stocker ...? <g>
--
Charlie...
ET1
Charlie Choc <cc...@bellsouthyourtrousers.net> wrote:
>jan...@pal.ECE.ORST.EDU (ET1) wrote:
>>
>>Anybody know what the field of view of a trout is?
>
>Wild, native, stocker ...? <g>
There's no such thing as a wild fish, once you've entered
it's field of view, it has been.....changed. :-)
ET1
Jon McAnulty <nospamm...@svm.vetmed.wisc.edunospam> wrote:
>ET1 wrote:
>
>> Hence the *NEAR* 360 degrees. Near is a relative term of course.
>> The general meaning being that a fish can see a good portion
>> of the world around it at any given time. I've long since forgotten
>> why this was important, but now curiousity has gotten the better
>> of me and I just have to know for my own peace of mind. :-)
>>
>
>40 degrees then that is a big enough chunk to not be NEAR in my book but your book may
>differ. People are quoting a lot of precise numbers so to fall back on NEAR as all
>inclusive of any variant is not a particularly compelling argument.
You are right, I'm not that picky. Being able to see 320 degrees
is damn near enough for me.
:-),
Walt Winter
ET1 wrote:
>
> There's no such thing as a wild fish, once you've entered
> it's field of view, it has been.....changed. :-)
> - Ken
now that *is* funny & timboretically correct!
waldo... thank god it's dinnertime....
Charlie Choc
>There's no such thing as a wild fish, once you've entered
>it's field of view, it has been.....changed. :-)
Very good, you 'saw' it coming<g>
--
Charlie...
Rusty Hook
> I would still like
> to
> know if fish can see directly behind them.
Yes. They do have a +/- 40 degree blind spot directly behind them, but
this is only relevant if a fish is sitting perfectly still. If you've
ever watched trout feeding, even when they're holding in a prime lie,
they're always in motion, enough that the so-called blind spot is
covered. Maybe not every second, but often enough to spot large
predators like us.
--
Rusty Hook
Laramie, Wyo
c...@uwyo.edu
Rusty Hook
> My question is, can fish see directly behind them? If so, what kind
of
> proof is there to support your claim?
> ...
> A horse can see almost everything but does have blind spots. A
horse's
> blind spots are at the very tip of his mouth, underneath him, and
> directly behind him. I thought fish would be the same due to their
eye
> placement.
Like a horse, a fish can't see directly behind itself, but, like a
horse, a fish can turn its head, and given its field of view, it
doesn't have to turn its head very much!
ET1
Mike Connor <MIKE-...@t-online.de> wrote:
>Trout have all round vision. They have binocular vision in an arc of about
>thirty degrees directly in front of their eyes, and a "blind spot" of about
>the same arc directly behind them. Immediately in front of its head and for
>about an inch above it a trout has no vision, and it has a similar but
>larger blind spot immediately below it. Between these blind spots in both
>vertical and horizontal planes are wide arcs of monocular vision. These
>suffice for general scanning and movement detection but do not allow the
>perception of distance, details or perspective. In order to achieve this the
>fish must turn its head so as to enable use of its binocular vision.
Thank you, that answers it for me.
Mr. Gink
Mike Connor wrote:
>
> Trout have all round vision. They have binocular vision in an arc of about
> thirty degrees directly in front of their eyes, and a "blind spot" of about
> the same arc directly behind them. Immediately in front of its head and for
> about an inch above it a trout has no vision, and it has a similar but
> larger blind spot immediately below it. Between these blind spots in both
> vertical and horizontal planes are wide arcs of monocular vision. These
> suffice for general scanning and movement detection but do not allow the
> perception of distance, details or perspective. In order to achieve this the
> fish must turn its head so as to enable use of its binocular vision.
>
> When at rest both trout and human eyes are focussed on infinity, but due to
> the different construction of a trout's eyes the depth of field is very much
> greater, this means that all objects more than about 65 cm away are
> simultaneously in focus. This greatly enhances the trout's ability to
> perceive movement outside its immediate vicinity. When the trout's eyes are
> focussed on something only a short distance away, depth of field is minimal
> and only sudden movements or changes in light intensity are detected.
> Immaterial whether in water or in air.
>
> The trout's perception of objects in air is controlled by the way light is
> refracted as it passes from air to water. The apex of the triangle creating
> the trout's "window", is fixed at ninety-seven degrees irrespective of the
> fish´s depth in water At a depth of one meter the trout's "window" is about
> two metres across, and at double the depth, the diameter of the window is
> also doubled. If it senses danger a trout will usually sink to greater
> depth, to put more distance between itself and the danger, but also to
> increase its field of vision.
>
> The trout owes its power of all round vision to the distribution of the
> cones in its retina, and to the actual position of its eyes. Trout eyes are
> designed to give maximum all round awareness.
>
> I checked these figures and explanations in two books after writing them,
> and they are exactly correct.
>
> TL
> MC
> --
> "In order to achieve what is possible, one must constantly attempt the
> impossible"
> http://www.mikeconnor.de
> "ET1" <jan...@pal.ECE.ORST.EDU> wrote in message
> news:89k63j$p4k$1...@news.NERO.NET...
--
Steve Zimmerman
>______ I would have given credits to the authors.
>
I think you would have claimed to *be* the author <g>.
--Steve
Mike Connor
Rusty Hook
> Granted. A 20 pound pike probably doesn't need to be afraid of
> much of anything, but if it didn't instinctively flee from movement,
it
> probably would have never lived long enough to get that big.
I agree. A pike that wasn't concerned about otters (or bear) wouldn't
last very long, 20 lbs or not.
Rusty Hook
> Boy, I'm sure no expert on fish physiology, but I think your concept
of this
> "vision cone" thing may be just a bit off. As I understand it, that
term
> and others like it refer to the trout's ability to see objects above
the
> surface.
It's got nothing to do with the design of the trout eye. It's physics.
Light refracts as it passes from air to water, distorting the image
within the cone. Outside the cone, light is hitting the water at such a
shallow angle that it's reflected away. This is true for a fish, a
human, or even a camera. There is a chapter in Presentation
called "What the Fish Sees" that describes a lot of this in detail, and
has some underwater photos to back it up.
Rusty Hook
> the goddam fish is not going to give a happy rat's ass about the
color
> of your line.
Underwater observation of trout has shown that they are disturbed least
by green fly lines than by other colors. Exactly why would be pretty
hard to answer, let alone prove, and presentation is definitely a much
larger factor than flyline color, but color is a factor, and when given
a choice, green seems to be best.
Rusty Hook
> Maybe white is the only viable color!
> Fire at will.
White is the worst color of all (same research).
Mr. Gink
Mike Connor
correct. However, it actually seems fair comment, as I did not discover
this information all on my lonesome to begin with. If you wish to check some
of these references you will find info in the following books:
"The Trout" A fisherman's natural history. Rupert Watson ISBN
1-85310-235-0
"Die Forelle und die Fliege" Fliegenfischen aus neuer Sicht ( Original
English title "The Trout and The the Fly" A new Approach") by J.Goddard and
J.B. Clarke ISBN 3-275-00803-X
"The New Compleat Angler" by Stephen Downes and Martin Knowelden ISBN
0-7481-0088-1
"TROUT" The wildlife series. 31 Authors. Fisheries and aquatic biologists,
zoologists, and limnologists.. Edited by Judith Stolz and Judith Schnell
ISBN 0-8117-1652-X
These were the books I checked directly to ensure that the information was
correct, but practically any reasonable book on trout will contain the same
information regarding their vision.
By the way this information applies specifically to trout. Other fish have
different characteristics.
Glad a man of real character and proven genius pointed out my abysmal
failure and attempted base deception in not giving credits.
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
"Mr. Gink" <gi...@tds.net> wrote in message news:38BDAF98...@tds.net...
Wayne Harrison
wrote:
>Vern wrote:
>> I would still like
>> to
>> know if fish can see directly behind them.
>
>Yes. They do have a +/- 40 degree blind spot directly behind them, but
>this is only relevant if a fish is sitting perfectly still. If you've
>ever watched trout feeding, even when they're holding in a prime lie,
>they're always in motion, enough that the so-called blind spot is
>covered. Maybe not every second, but often enough to spot large
>predators like us.
>
>--
>Rusty Hook
>Laramie, Wyo
>c...@uwyo.edu
>
now *there* is some perceptive information for ya, vern.
wayno
R Dean
wrote:
>I wrote it myself. I only checked the books to make sure the information was
>correct. However, it actually seems fair comment, as I did not discover
>this information all on my lonesome to begin with. If you wish to check some
>of these references you will find info in the following books:
>
>"Die Forelle und die Fliege" Fliegenfischen aus neuer Sicht ( Original
>English title "The Trout and The the Fly" A new Approach") by J.Goddard and
>J.B. Clarke ISBN 3-275-00803-X
John Goddard's "Trout Fishing Techiniques" has quite a bit as well...AND he
gives credit as to where the info is not his own...oughta make Ginky happier
than....
>
>Glad a man of real character and proven genius pointed out my abysmal
>failure and attempted base deception in not giving credits.
>
Really? When? Who? Imagine, picking on your Wholly Flatulent Sub Potentate,
not to mention the Duke of Earl, and the Savior of the Crescent City, Lafitte.
BTW, who is the ROFFian "Dominic You"?
HTH?
R
JeffC 1474
>can't see nearly 360 degrees. A fisheye lens has a field of view
>of 180 degrees (I checked). Since a fish's eyes are on opposite
>sides of it's head, it should be able to see nearly 360 degrees.
They can see nearly 360 degrees. But the sides of their heads are not
parallel. The binocular cone in front is bigger than the blind spot in back.
That's because a fish's head widens slightly from snout to gill. That angles
the fish-eye lenses forward slightly.
Regards,
Jeff
JeffC 1474
>designed to give maximum all round awareness.
Not really. Maximum all round awareness would mean full sight in every
direction, which they do not have. Their eyes are designed for near-all-round
awareness.
Regards,
Jeff
rw
Mike Connor wrote:
>
> Trout have all round vision. They have binocular vision in an arc of about
> thirty degrees directly in front of their eyes, and a "blind spot" of about
> the same arc directly behind them. Immediately in front of its head and for
> about an inch above it a trout has no vision, and it has a similar but
> larger blind spot immediately below it. Between these blind spots in both
> vertical and horizontal planes are wide arcs of monocular vision. These
> suffice for general scanning and movement detection but do not allow the
> perception of distance, details or perspective. In order to achieve this the
> fish must turn its head so as to enable use of its binocular vision.
Binocular vision is not necessary for depth perception. It's useful, but
by no means necessary. There are many other cues for depth. If you doubt
this, just close one eye and see if you can walk around without bumping
into things. For that matter, why can you perceive depth in a painting
or a photograph? I sometimes play tennis with a guy that has only one
eye, and he's pretty darn good.
I doubt whether binocular vision is very important to fish at all.
--
visit my web site: http://home.earthlink.net/~royalwulff/
Please reply to royalwulff@REMOVE_THISearthlink.net. (Reply-to set to
something bogus to avoid spam)
rw
CodeMarine wrote:
>
> Ok, here are the details. The pond where I fish is man made, with no cover.
> The fish (bass, bream) hug the shoreline (ie. from 6 inches to 6 feet from
> the bank), in clear water often no deeper than a foot or two. So I walk
> along casting almost parallel to the shoreline, probably an average casting
> distance of say 25'.
>
> I should point out that there is a walking path that encircles the pond no
> more than about 10 feet from the shore, so the fish are used to people and
> dogs running by. That doesn't seem to make them bolt. Oh, yeah, and I know
> they bolt because they are so close to the surface that I can see the wake.
>
> If I walk along without casting, I can get fairly close to the
> fish--probably within 10-15 feet or so. But if I cast over the top of them,
> even from a further distance, they bolt. It might be the movement of my arm,
> but I suspect it is the line or the shadow thereof directly above them that
> sets them off. I'm not the best caster in the world, mind you, but the bolt
> does definitely happen *before* the line splashes down into the water.
Use a float tube and cast to them from the other side (i.e., from out in
the pond). You'll slay 'em.
V. Ursenbach
Yes, someone can use "perspective" to determine distance. But, this is
not the same thing as "depth perception" (3D vision).
Let's do your test and close one eye. Yes you can tell what is closer
and what is farther due to their position, angles, and shadows.
However, the image will appear flat like a photo.
Now open the other eye and objects will appear 3-dimensional. It's
like looking through a child's 3D view-finder, some items will appear
closer regardless of perspective.
Think about your last trip to the DMV where they asked you to look
through a strange looking view-finder and tell them which "X" is
closer. The only thing in the view-finder were two "Xs." There were
no shadows, no angles, and the "Xs" were the same size. There was
nothing else to tell you which one is closer other than your "binocular
vision." "Binocular vision" is mandatory to have a true 3D experience.
I don't want to discount your post. Because, I think fish as humans
can determine distance with only one eye. However, this is not what is
normally referred to as "depth perception."
--
Vern
My ROFF page:
http://msnhomepages.talkcity.com/ResortRd/v_deloy/ROFFintro.html
Charlie Choc
>I think you would have claimed to *be* the author <g>.
>
I think you *know* he would have<g>.
--
Charlie...
rw
"V. Ursenbach" wrote:
>
> RW,
>
> Yes, someone can use "perspective" to determine distance. But, this is
> not the same thing as "depth perception" (3D vision).
>
snip
> "Binocular vision" is mandatory to have a true 3D experience.
>
> I don't want to discount your post. Because, I think fish as humans
> can determine distance with only one eye. However, this is not what is
> normally referred to as "depth perception."
>
Vern,
I spent quite a bit of my professional career as a scientist studing and
developing computational models of vision. My specialties were stereo
vision and perspective. I've written quite a few technical papers on the
subject. If you look in the Encyclopedia of Artificial Intelligence
(John Wiley and Sons) under the topic "Stereo Vision" you'll find that I
wrote the entry. While I'm not an expert in fish vision in particular, I
do know a bit more about the the general topic of vision than the
average person.
Well developed stereo vision is found in warm blooded predators and
primates. Their eyes face forward, they have relatively narrow fields of
view with lots of overlap of the visual fields, and they have highly
foveated retinas for seeing very fine detail. This arrangement is ideal
for stereo vision.
Prey animals like horses and trout have eyes facing toward the sides
with wide fields of view, little overlap of the visual fields, and
relatively nonfoveated retinas. This arrangement is very poorly suited
to stereo vision. Horses probably have some stereo vision, but it's
certainly very poor compared to that of humans, dogs, and eagles. It may
be possible that trout have some rudimentary stereo vision, but I doubt
it, and if they do then purely geometrical considerations would dictate
that it would only be effective at very short distances, like a few inches.
There's a way to get the same geometrical effect as stereo without
actually using stereo vision. It's called motion parallax. If you close
one eye and move your head back and forth you'll notice that the
relative positions of objects shift, and the closer the object the
greater the shift. This shift is called "disparity", and it's exactly
the same principle that makes stereo vision work. I think it's very
likely that trout use motion parallax for depth perception.
BTW, a significant percentage of humans are "stereo blind", meaning that
they've never developed the ability to see in stereo, even though their
vision in each eye may be otherwise normal. Most people who are stereo
blind never even realize it.
Mike Connor
essential to trout. They would be unable to feed without it. This is the
conclusion of many scientists and various other authors.
TL
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
"rw" <nos...@earthlink.net> wrote in message
news:38BDE002...@earthlink.net...
Mr. Gink
Goes to show you how many are once again wrong?
Mr. G.
Mike Connor wrote:
>
> According to all the books I have read on this subject binocular vision is
> essential to trout. They would be unable to feed without it. This is the
> conclusion of many scientists and various other authors.
>
> TL
> MC
rw
Mike Connor wrote:
>
> According to all the books I have read on this subject binocular vision is
> essential to trout. They would be unable to feed without it. This is the
> conclusion of many scientists and various other authors.
You can find all sorts of arrant nonsense in books, Mike. There's a
lamentable tendency to assume that if an animal's two visual fields
overlap, even slightly, that they have stereo vision. That's bullshit.
Human stereo vision is far more limited than most people realize. It's
extremely useful for threading a needle or tying a #24 fly on an 8x
tippet, but it degrades sharply with increasing distance. At a distance
of about 10 meters stereo vision is still somewhat effective, but beyond
that it's nearly useless. Optical aids like binoculars are required to
make it work.
BTW, I've caught otherwise healthy trout that have only one eye.
Mike Connor
are usually transparent. They feed mainly by the senses of taste/smell, and
use of the lateral line, which means they do not normally take floating
flies. Such fish have other highly developed senses to help them survive and
avoid predators.
Normal trout are mainly sight feeders in regard to their usual food. They
will take worms and other things, and could do this even if blind . However
they require binocular vision in order to focus on their usual prey, and
are obliged to turn their whole bodies to do this, as they are unable to
turn their heads independently. Blind trout would normally be bottom
feeders, ( now where have I heard tat before ? ), and they would not survive
long, as their acute vision is their main protection against predators.
These discussions are somewhat pointless, as a great deal of research has
been done in this area, and the facts and conclusions are well documented.
It is simple enough to obtain these facts, and various opinions for or
against will not change them. Arguing semantics, as to whether "all-round
vision" means 360° or 330° is pointless in the extreme. It is accepted by
practically all authorities that "all-round vision" is the correct term for
this capability, and this is what trout possess.
This passage from "The Trout" by Rupert Watson, which I mentioned in an
earlier post, might be of interest
"Sight"
Sight is crucial to the fundamental survival activities of feeding, sensing
and avoiding danger, moving and breeding. Indeed, much of the trout´s way of
life is conditioned by its visula abilities which themselves derive from the
anatomical structure and positioning of its eyes and from the behaviour of
light in water.
Superficially, a trout´s eye resembles its humna counterpart. Both have an
outer transparet cornea, the trout´s protruding slightly from the side of
its head. Beneath the cornea is the coloured iris which surrounds the pupil.
A trout´s pupil is simply a hole in the iris that allows light through the
clear lens in the eye, then to be focussed on the retina. In the retina are
millions of photoreceptive cells. These are either rods or cones and contain
pigments that react chemically to light, thereby transmitting nervous
impulses to the brain where the information received is transformed into an
image.
Rod cells are in constant use, especially during periods of poor light; they
cannot discern colour but are particularly important in the perception of
minute detail. Rods may be up to one thousand times as sensitive as cones
which can detect colours and fünction when light is particularly bright. In
the retinas of fish living in murky, light-starved waters on the sea bed
there are often only rods and no cones. They are therefore colour-blind
although their eyes are often acutely sensitive to the deep blue wavelengths
of light which penetrate the depths. Trout's eyes are adequately supplied
with both rods and cones giving them potentially good colour vision in a
bright enough environment. Water first absorbs red light waves, then orange,
yellow and green. Less than ten per cent of red light penetrates as far down
as four meters, so wet flies dressed with red materials soon lose their
colours in quite shallow water; orange and yellow last to greater depths but
not as far as green which holds out quite as far as any artificial fly is
likely to sink.
Light is quickly absorbed by water and the eyes of fish are better adapted
for vision in poorer light than those of land-dwelling vertebrates. In
twilight and semi-darkness a trout's sight is far superior to a human's.
However, in optirnum lighting conditions human sight is many times more
powerful than that of trout which must come very close to their prey to
confirm its identity.
Unlike the human eye, a trout's has no eyelids and there are three other
principal areas of distinction - the shape of the lens, its focussing
mechanism and the distribution of rods and cones in the retina. All are
consequential differences of the trout's shape or of its aquatic
environment.
Light passing into a human eye travels from air into the much denser matter
of the cornea; there it bends by refraction in the same manner as light
entering water. The human cornea is responsible for much of the initial
foctising which is then fine tuned by the lens. Light entering a trout's eye
does so directly from an equally dense medium - water - and therefore there
is no refraction at the cornea and all focusing is undertaken by the lens.
This is extremely powerful and actually protrudes through the pupil enabling
the trout to look almost straight up and down as well as backwards and
forwards. It also makes the lens more susceptible to accidental damage.
The focusing mechanism of the human eye centres round the lens' ability to
change shape, using muscles fixed to its top and bottom. A trout does not
possess this ability, instead focusing by moving the entire lens forwards or
backwards, as in a telescope, to create the required clarity of image on the
retina, The amount of light entering a human eye can be controlled by
adjusting tbe iris, which expands or contracts the size of the pupil;
however the protrusion of the trout's lens through the iris precludes this
and there are particular retinal cells to counteract the otherwise
potentially damaging effect of a sudden invasion of brighter light.
Rods and cones in a trout's eye are uniformly distributed over the retina -
a direct consequence both of the fish's inability to move its head easily
from side to side and of the positioning of its eyes which give almost
all-round vision. In a human eye, cones are densely concentrated round a
central point in the retina (fovea) which results in acutely sensitive
daylight vision within a small arc of about five degrees. By moving the eyes
but not the head, visual acuity becomes noticeably less but this is easily
overcome by simply turning the head so that most of the light continues to
focus on the fovea. The cones in a trout's eye are far more evenly
distributed, giving it much greater all-rouind vision without any head
movement but no area of acutely perceptive daylight sight.
A trout owes its power of all-round Vision not only to the distribution of
the cones in its retina but also to the actual positioning of its eyes. just
like any bird that has eyes on the side of its head, this gives trout an
area of binocular vision in an arc of sorne thirty degrees in front of it
and a blind spot of a roughly similar arc directly behind; immediately in
front of its head and for an inch or so above, a trout has no Vision and it
has a corresponding but larger blind spot directly below it. Between these
blind spots in both the vertical and horizontal planes are wide arcs of
monocular vision. These are enough for general visual scanning and the
detection of movement, but not suflicient to perceive distance, detail and
perspective. For this, a trout must bring its binocular vision into play by
pointing its head, usually through movement of its whole body, at the
particular object on which it wishes to focus. Trout must continually avoid
becoming a meal for some larger predator as they seek out their own food,
and their eyes are designed to provide maximum all round awareness. Pike,
which have little to fear from aquatic predators other than their own kind,
have their eyes well forward, giving a large area of easy binocular Vision
but also a bigger blind spot behind their head.
At rest, both trout and human eyes are focused on infinity, but the former's
depth of field is considerably greater with the result that all objects more
than about seventy centimeters away are simultaneously in focus. This
greatly enhances a trout's ability to perceive movement, food or other
details outside its immediate vicinity. When focused on something only a
short distance away, depth of field is minimal and only sudden movements or
changes in light intensity are detectable outside this immediate area of
close-up focus, whether in the water or the air beyond.
A fish's perception of objects in the air is dominated by the refractive
behaviour of light as it passes from air to water, clearly demonstrated by
the apparent bending of a stick that is stuck into the water at an angle.
This has given rise to the concept of the trout's 'window'which describes
what and how it can see above the surface of the water.
The degree of refraction of light rays entering water depends upon the angle
at which they strike its surfäce. Below ten degrees from the horizontal
almost no light penetrates the surface. Thereafter, as the angle increases
so does the amount of light entering the water. At the same time, distortion
decreases until light directly above a fish enters the water with no
distortion at all - so the stick standing upright in the water appears quite
as straight as it is. The effect of this refraction is that light from an
arc of about 160 degrees above the surface (ten degrees off the horizontal
on either side) is compressed into a window of ninety-seven degrees within
the water. Objects on the perimeter of that arc, such as the tip of a rod,
look compressed and blurred in the window, while those in the centre are
detected with greatest clarity and minimum distortion. However, the colour
of a fly silhouetted against the sky directly above a trout's head is
obviously less discernible than if it was floating down nearer the edge of
the window.
The apex of the triangle creating the trout's window is fixed at
ninety-seven degrees irrespcctive of the fish's depth in the water. So the
deeper a fish's position, the greater the area of its window, although
vistial ability is reduced with depth simply by the absorption of so much
light by water. At a depth of one meter a trout's window is just over two
meters across and at double the depth, the diameter of the window is also
doubled. Sensing danger, a trout will sink lower, not only to put more
distance between itself and the source of its unease but also to give it a
wider field of vision.
Confined as it is to viewing only through a circular window, it follows that
a trout is unable to see through the surface of the water anywhere beyond
the window's edge. This area is called the 'mirror'and reflects the bottom
of the lake or river bed on the underside of the surface film. Any object on
the surface of the water, outside the area of the window, is quite
undetectable but a trout almost certainly uses the optical effect of the
mirror of its world as an aid to catching underwater prey reflected in it.
Both mirror and window only operate effectively when the stirface of the
water is relatively calm. lf ruffled by current or wind, visibility in both
is seriously reduced making feeding a much more haphazard undertaking - and
Fishing far less of a challenge.
QUOTE ENDS
If you wish to trash posts about scientific facts then read about them, so
that you are able to discuss them sensibly, mention your sources please, and
refrain from making silly comments.
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
"Mr. Gink" <gi...@tds.net> wrote in message news:38BE646F...@tds.net...
Jon McAnulty
> In article <38BD9DBD...@svm.vetmed.wisc.edunospam>,
> Jon McAnulty <nospamm...@svm.vetmed.wisc.edunospam> wrote:
> >ET1 wrote:
> >
> >Right and it depends on how picky you want to get and how near NEAR really is. If it is
> >40 degrees then that is a big enough chunk to not be NEAR in my book but your book may
> >differ. People are quoting a lot of precise numbers so to fall back on NEAR as all
> >inclusive of any variant is not a particularly compelling argument.
>
> You are right, I'm not that picky. Being able to see 320 degrees
> is damn near enough for me.
>
> :-),
> - Ken
Would that be referred to as near-sightedness?
;-)
Jon
>
>
Jon McAnulty
> Trout have all round vision. They have binocular vision in an arc of about
> thirty degrees directly in front of their eyes, and a "blind spot" of about
> the same arc directly behind them. Immediately in front of its head and for
> about an inch above it a trout has no vision, and it has a similar but
> larger blind spot immediately below it.
This explains why my preternaturally accurate casts right between the eyes
results in trout acting as if they haven't seen my fly at all.
I feel, strangely, better somehow.
;-)
Jon
Mike Connor
than good sense I fear. Whatever, while you obviously know a great deal
about human vision, and some of this is doubtless more or less directly
transferable to other vertebrates, I have now checked seven of my books, and
they all say basically the same thing with regard to trout. It follows
therefore, that what they say is unlikely to be arrant nonsense, especially
as these books are from some of the most prominent biologists, zoologists
etc extant.
This whole discussion started because a specific question was asked as to
the trout愀 field of view. For all practical purposes, and irrespective of
the various details involved, a trout has "all-round vision", with a large
blind spot of about thirty degrees directly behind it, and one or two other
relatively minor blind spots in the head area. It can detect rapid
movement and changes in light intensity easily, anywhere in its field of
view ( including rapidly moving shadows etc,cast by fly-lines and the like).
It needs to get close to its prey and point its head directly at it in order
to see it properly using binocular vision. Binocular simply means "using
both eyes" in this case. Whether this implies "stereoscopic vision" or not I
do not know, it is not mentioned in any of my texts. What is certain is
that it needs this binocular capability to inspect its prey properly.
The universal opinion of all authorities consulted to date, is that a
trout愀 eyes are designed to give maximum all round awareness. They also
concur in the matter of binocular vision being crucial to taking food
normally. Other senses are also discussed in connection with this, but as
this discussion was basically on sight, I did not see much point in bringing
in any other perhaps confusing details.
I have also caught trout which were blind in one eye. This is however a
fluke, as these fish would normally very quickly fall play to predators.
Their whole system reflects their blindness, their protective coloration on
the blind side deteriorates rapidly, ( this is directly controlled by their
visual perception, among other things ), and these fish only normally
survive if they find a lie which offers them more than normal protection. I
distinctly remember three such fish, all were caught from such lies, between
tree roots, where they would normally be unapproachable except by an angler,
and then only with a lot of luck.
TL
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
"rw" <nos...@earthlink.net> wrote in message
news:38BE64D8...@earthlink.net...
rw
Jonathan Cook wrote:
>
> On Wed, 01 Mar 2000 23:51:35 GMT it appears that Rusty Hook wrote:
> : Vern wrote:
> :> I would still like
> :> to
> :> know if fish can see directly behind them.
>
> : Yes. They do have a +/- 40 degree blind spot directly behind them, but
>
> Do fish's eyes move in their sockets?
No, they don't.
Wolfgang
Mike Connor wrote:
> I checked these figures and explanations in two books after writing them,
> and they are exactly correct.
Yeah right! Nice try Mike. First you write two books and then you use them to
check your facts? Uh huh, we're gonna to swallow that! :)
Mike Connor
do tend to make quite a few mistakes. Ah well. For what it is worth I am
indeed currently writing a book, but it has nothing to do with trout vision.
I noticed quite a few mistakes in one of my other replies as well, Perhaps
my binocular vision is not as it should be. Mind you I am better off than
most trout, I can type blind, and the mistakes are rarely fatal.
Some of your comments are becoming very cryptic of late as well I quote "
Uh huh, we're gonna to swallow that! :)"
Fortunately I always make allowances for the fact that these things might
indeed be some popular Americanism, of which I am as yet blissfully
ignorant. It might of course also be that I have not the faintest idea of
what some people are talking about ! :)
What I really wanted to ask is , is there any visible charring evident from
your recent experience ? Just purely for informational purposes, one of my
customers gave me a bottle of Famous Grouse, and I can only think of one
really sensible use for it !
TL
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
"Wolfgang" <wolf...@post.its.mcw.edu> wrote in message
news:38BE7C37...@post.its.mcw.edu...
Wolfgang
Mike Connor wrote:
> .......I.......make........mistakes.
Egad Man, do you have any idea of what a dangerous precedent you have just
set??!! Any lesser creature would immediately be banned from the committee for
such an offense!
> Some of your comments are becoming very cryptic of late as well I quote "
> Uh huh, we're gonna to swallow that! :)"
Merely a hybrid of one of the fishy aphorisms that showed up here a few months
ago; "hook line and sinker".
> .........I have not the faintest idea of
> what some people are talking about ! :)
Sadly, I DO have an idea of what they are saying, indicating that I am perhaps
becoming as deranged as the originators of what should be entirely
incomprehensible posts. Your failure to grok should be viewed as a positive
sign.
> What I really wanted to ask is , is there any visible charring evident from
> your recent experience ? Just purely for informational purposes, one of my
> customers gave me a bottle of Famous Grouse, and I can only think of one
> really sensible use for it !
Still smoldering enough to keep a couple of pesky fire fighters lurking about.
But at least I have ceased to cause combustion in flammable substances merely by
walking by them. By the way, I never did thank you for the lovely eulogy. Next
time I self destruct (and I'm sure it won't be long before the anguish of
another newby prompts me to do so) I'd like nothing better than to have you
reprise your performance.
Here's lookin at YOU kid!
ET1
>
>I spent quite a bit of my professional career as a scientist studing and
>developing computational models of vision. My specialties were stereo
>vision and perspective. I've written quite a few technical papers on the
>subject. If you look in the Encyclopedia of Artificial Intelligence
>(John Wiley and Sons) under the topic "Stereo Vision" you'll find that I
>wrote the entry. While I'm not an expert in fish vision in particular, I
>do know a bit more about the the general topic of vision than the
>average person.
Very cool! I actually spent a good deal of time doing robotics work
and modelling of neural structures with hardware and software. I'm
sure I have that book stuffed away in a box somewhere, I'll have
to try to find it and take a look.
- Ken
--
"I went to the woods to live deliberately, to front only the essential facts
of life, and see if I could not learn what it had to teach, and not, when
I came to die, discover that I had not lived." - Henry David Thoreau
ET1
>
>
>Jonathan Cook wrote:
>>
>> On Wed, 01 Mar 2000 23:51:35 GMT it appears that Rusty Hook wrote:
>> : Vern wrote:
>> :> I would still like
>> :> to
>> :> know if fish can see directly behind them.
>>
>> : Yes. They do have a +/- 40 degree blind spot directly behind them, but
>>
>> Do fish's eyes move in their sockets?
>
>No, they don't.
Are you sure, I could have sworn they could move somewhat?
Looks like it's time to head out for more feeder fish to
test this hypothesis. My turtles are going to get to like
this trend. :-)
rw
Mike Connor wrote:
>
> You can find arrant nonsense all over the place, there is more of it about
> than good sense I fear. Whatever, while you obviously know a great deal
> about human vision, and some of this is doubtless more or less directly
> transferable to other vertebrates, I have now checked seven of my books, and
> they all say basically the same thing with regard to trout. It follows
> therefore, that what they say is unlikely to be arrant nonsense, especially
> as these books are from some of the most prominent biologists, zoologists
> etc extant.
You have more faith in received scientific wisdom than I do, Mike. What
often happens is that an "authority" makes an unsupported assertion --
like for example that fish have stereo vision because their visual
fields overlap slightly -- and then that assertion is repeated
uncritically by others and it eventually becomes "common wisdom".. Maybe
fish do have stereo vision, but I've never heard of any experiments that
support it.
>
> This whole discussion started because a specific question was asked as to
> the trout愀 field of view. For all practical purposes, and irrespective of
> the various details involved, a trout has "all-round vision", with a large
> blind spot of about thirty degrees directly behind it, and one or two other
> relatively minor blind spots in the head area. It can detect rapid
> movement and changes in light intensity easily, anywhere in its field of
> view ( including rapidly moving shadows etc,cast by fly-lines and the like).
> It needs to get close to its prey and point its head directly at it in order
> to see it properly using binocular vision. Binocular simply means "using
> both eyes" in this case. Whether this implies "stereoscopic vision" or not I
> do not know, it is not mentioned in any of my texts. What is certain is
> that it needs this binocular capability to inspect its prey properly.
No disagreement here. The only thing I'm sceptical about is whether they
use binocular vision for depth perception. I understand the fact that
you're not claiming that they do.
>
> The universal opinion of all authorities consulted to date, is that a
> trout愀 eyes are designed to give maximum all round awareness. They also
> concur in the matter of binocular vision being crucial to taking food
> normally. Other senses are also discussed in connection with this, but as
> this discussion was basically on sight, I did not see much point in bringing
> in any other perhaps confusing details.
>
> I have also caught trout which were blind in one eye. This is however a
> fluke,
The ones I caught were trout. :-)
rw
ET1 wrote:
>
> In article <38BE70A6...@earthlink.net>, rw <nos...@earthlink.net> wrote:
> >
> >
> >Jonathan Cook wrote:
> >>
> >> Do fish's eyes move in their sockets?
> >
> >No, they don't.
>
> Are you sure, I could have sworn they could move somewhat?
> Looks like it's time to head out for more feeder fish to
> test this hypothesis. My turtles are going to get to like
> this trend. :-)
I have to adnit that I'm not 100% sure, but I don't think so. I like
your sceptical attitude! Look at your fish and find out, then let us know.
Mike Connor
report. However, I do tend to accept lucidly presented facts backed up with
excellent reasoning in support of some conclusions. Basically I have no
real choice in the matter in most fields, as it is obviously impossible for
one man to have even a relevant percentage of the span of human knowledge at
his fingertips.
Like most other people I am dependent to a considerable extent on the
observations, scientific endeavour and reasoning of others, in nearly all
fields of interest. First hand scientific knowledge of many things is
unattainable for most of the human race in any case. They are far too busy
eating, breeding, killing each other, destroying their environment,
struggling to eat and breed etc etc etc to take much notice of what is
actually occurring around them.
I acknowledge your doubts on the wisdom of accepting unsupported assertions
from authorities, based simply on the fact that they are considered to be
authorities, and I I would seldom accept such statements, as far as they
were of any concern to me, without attempting to at least satisfy myself
that they were factually based and the result of sensible and logical
reasoning.
It has always struck me as being somewhat amusing ( not ! ) that quite a few
intelligent people spend their lives attempting to uncover facts and new
knowledge, a certain percentage spend their time attempting to implement
practical applications of these facts and knowledge, a certain percentage
spend their time bending and moulding the facts to suit their own purposes,
a much larger percentage spend their time attempting to cover up facts and
new knowledge or indeed lying about it, thus frustrating those attempting
implementation, and many people either do not know this or do not care.
It is very difficult to come up with irrefutable facts on a great number of
subjects, it is even more difficult to persuade others to accept these based
on logic, and the vast majority do not care anyway.
TL
MC
--
"In order to achieve what is possible, one must constantly attempt the
impossible"
http://www.mikeconnor.de
"rw" <nos...@earthlink.net> wrote in message
news:38BE9DF2...@earthlink.net...
rw
Mike Connor wrote:
>
> Between these
> blind spots in both the vertical and horizontal planes are wide arcs of
> monocular vision. These are enough for general visual scanning and the
> detection of movement, but not suflicient to perceive distance, detail and
> perspective. For this, a trout must bring its binocular vision into play by
> pointing its head, usually through movement of its whole body, at the
> particular object on which it wishes to focus.
This is an example of what I consider to be an unsupported assertion. In
fact, the relatively unfoveated, wide-angle nature of a trout's visual
system, as described earlier in the "snipped" part of this quote, argues
against this assertion for implied geometrical reasons. The acuity of
stereo depth perception is roughly proportional of the baseline (the
distance between the eyes) and the sampling rate (the density of the
receptors in the retina). Trout lose on both points -- small baseline
and low density.
rw
Mike Connor wrote:
>
> It has always struck me as being somewhat amusing ( not ! ) that quite a few
> intelligent people spend their lives attempting to uncover facts and new
> knowledge, a certain percentage spend their time attempting to implement
> practical applications of these facts and knowledge, a certain percentage
> spend their time bending and moulding the facts to suit their own purposes,
> a much larger percentage spend their time attempting to cover up facts and
> new knowledge or indeed lying about it, thus frustrating those attempting
> implementation, and many people either do not know this or do not care.
Well said, Mike. I couldn't agree more.
Mr. Gink
Mike Connor wrote:
snipped book review to save space:
>
> Both mirror and window only operate effectively when the stirface of the
> water is relatively calm. lf ruffled by current or wind, visibility in both
> is seriously reduced making feeding a much more haphazard undertaking - and
> Fishing far less of a challenge.
>
> QUOTE ENDS
________ hum? I do a lot of nymphing. I guess that doesn't count?
V. Ursenbach
an educated man like you are. I've never heard of "Stereo Vision" or
"motion parallax" so I will just have to take your word on it.
rw
"V. Ursenbach" wrote:
>
> I have to bow down to your expertise. I'm just a simple actor and not
> an educated man like you are. I've never heard of "Stereo Vision" or
> "motion parallax" so I will just have to take your word on it.
You're missing the point, Vern. Don't take anyone's word for it. I'm not
intending to argue from authority. I just sketched my credentials so
you'd take me seriously. I'm eagerly awaiting Ken's observations on
whther his feeder fish move their eyes when his turtles come hurdling up
from the depths, jaws agape.
Jon McAnulty
> I have to bow down to your expertise. I'm just a simple actor and not
> an educated man like you are. I've never heard of "Stereo Vision" or
> "motion parallax" so I will just have to take your word on it.
>
You can experience these phenomena yourself as you go from the former to
the latter as you work your way down through a bottle of single malt.
Science for the home.
Jon
Wayne Harrison
wrote:
>I have to bow down to your expertise. I'm just a simple actor and not
>an educated man like you are. I've never heard of "Stereo Vision" or
>"motion parallax" so I will just have to take your word on it.
>
>--
>Vern
>
hell, vern, get that chin up! after all, ronald reagan was a
simple, uneducated man...
wayno
Jeffrey Miller
Mike Connor wrote:
>
>... and refrain from making silly comments.
>
> MC
>
> --
uh, mike...that's a bit harsh, don't ya think??
jeff (...else, what's a roff for)