Color change with distance????

[RickZieger 0]

You may want to get a copy of the book "What Fish See".

He discusses this a lot.

 

Rick

[SilverCreek 0]

and as to all the charts and graphs and graphics pertaining to "how colors appear to fish"...

 

It's all guesswork until a fish produces a chart or a graph or a graphic. What if that fish is colorblind like some humans? There is no way, with 100% certainty, for any person to accurately describe the way a fish's brain interprets the signals sent to it from that particular fish's eye(s).

 

You can dissect fish eyes and count rods and cones under a microscope, study optic nerves, study visual cortex responses, and it still does not mean you understand what a fish SEES.

 

 

There have experiments to show that fish distinguish colors. For example, scientists put up an underwater color chart and the fish hits the specific color to be fed. Then they change the position of the colored button and the fish hits the correct color button to be fed.

 

There is also work on the color receptors (cones) of fish and the spectrum of wavelengths that they respond to. Fish also have one more cone (4 rather than 3) than humans. Three of them cover the spectrum of humans. The other is in the UV spectrum and is mainly in young fish and also is thought to become active during spawning. Hence the recent "marketing" of UV dubbing.

 

One would expect this from evolution, that is if evolution is true and human eyes would be the result of development of eyes in more primitive species.

 

There is other "practical evidence that fish "see" colors the same way that humans see colors. For example evolution of prey species have evolved to match the color and pattern of their surroundings. If color was not important, natural selection would not have selected AGAINST those in the species that did not match the color of their surroundings. So we know that predator fish use color to identify prey since their prey have evolved to camouflage themselves by matching background colors. Since the color matching of the prey also makes it diffiult for humans to see the prey fish, by deductive reasoning, we must be seeing the colors in the same way as the predator fish.

 

On a practical basis, we experientially know that fish see colors in the same way that we see colors. If that were not so, why do we match the color of the natural on our flies??????

 

If you deny that fish can see colors like we do, then I question becomes how deep is than belief? Tie your patterns with random colors and do not match the hatch.

 

With all due respect to you, I will go where the evidence leads. Experimental and anatomic evidence demonstrates that fish see the same colors that we do and practical evidence from matching the hatch confirms the experimental and anatomic studies. So I will match the color of the naturals when I fish.

[mikechell 0]

Well stated, Silver, and I agree that evolutionary similarities are numerous. The fact that the "construction" of the eye is almost identical, we see things the same as the fish.

I really agree with your statement, "Since the color matching of the prey also makes it difficult for humans to see the prey fish, by deductive reasoning, we must be seeing the colors in the same way as the predator fish."

 

With all that agreement, I also have to disagree with, "If you deny that fish can see colors like we do... Tie your patterns with random colors and do not match the hatch."

In the extreme, say fish see red as we see green ... then you would still "match the hatch" so the fish see the same colors as the "hatch", even if that color isn't the same as what we see.

How many pure white, purple, "fire tiger" or any other brightly colored prey do you see in nature? Yet, we tie flies of those, and wilder, colors all the time.

 

As JS said ... there really isn't any way to know for sure, without tapping into the brain of a fish and actually seeing with it's eyes. Even then, we would interpret what we see with our minds ... which is not like a fish's mind at all.

Lots of fun to think about and discuss ... no real value unless you're catching more than everyone around you because something you tied is attracting more fish attention.

[SilverCreek 0]

 

 

With all that agreement, I also have to disagree with, "If you deny that fish can see colors like we do... Tie your patterns with random colors and do not match the hatch."

In the extreme, say fish see red as we see green ... then you would still "match the hatch" so the fish see the same colors as the "hatch", even if that color isn't the same as what we see.

How many pure white, purple, "fire tiger" or any other brightly colored prey do you see in nature? Yet, we tie flies of those, and wilder, colors all the time.

 

As JS said ... there really isn't any way to know for sure, without tapping into the brain of a fish and actually seeing with it's eyes. Even then, we would interpret what we see with our minds ... which is not like a fish's mind at all.

 

 

 

Mike,

 

A fish CANNOT "see" green as we "see" red.

 

By definition green is a wavelength of radiation which is not a color but a band of radiation. The response of our brain interprets that radiation as the color green. The cone in the fish responds to the radiation and the fish's brain interprets that radiation. Lets call the interpretation of the fish the color "xyz."

 

So in the case above, "Green" corresponds to a radiation band. Therefore "Red" cannot be Green. Red is a different radiation and the fish would respond differently to the radiation band that we see as Green from the one that is Red.

 

The important thing is NOT the name that we attach to the radiation band, it is the fact that humans and fish "see" different radiation spectra as different from each other AND that when we see a color (radiation wavelength) and use that color in a fly, the fish "sees" the identical radiation wavelength. It really matters not that the fish's brain and the human's brain interpret the signal as the same interpretation, it is the fact that the radiation is unique and when we use our brain to match the radiation, it is the identical radiation that the fish sees.

 

So in the example above, green to us is "xyz" to the fish; but by matching green, we match xyz, since we are matching the radiation band. So green can NEVER be red since the radiation band for red is different from green.

 

As long as we can use the colors we see to match the identical radiation spectrum that the fish sees, we can match the "color" that the fish sees because we are matching a radiation specturm and not a color.

 

Does that make sense?

 

We DO NOT NEED TO KNOW how the fish actually interprets color spectrum to actually match the color spectrum.

 

Here's an example from physics. We have Newton's law of gravitation and the physical laws work so that we can send predict the position of Pluto years in the future and send the New Horizon probe meet up with Pluto. Yet we know from Einstein that gravity is not an attraction wave but the bending of space by mass. Even though Newton was wrong about gravity, the formulas and laws work. Similarly, we do not actually need to know exactly how the fish's brain works to make observations and to use those observations to match colors. If a fish can match the color red to get food, we know that it tell the color red from other colors. And by using other shades of red for buttons that do not give food, we can tell that fish can tell different shades of red apart from each other.

 

As for tying flies in colors that do not match the natural, that is a purposful decision on our part; and when we do that, we know that we are NOT matching the color that the fish sees. I guess I do not understand how that example of purposefully not matching the color shows that we cannot match the color when we do want to match the color.

[mikechell 0]

 

In the extreme, say fish see red as we see green ...

 

 

Mike,

 

A fish CANNOT "see" green as we "see" red.

 

 

Silver ... I was using that "extreme" as an example ... to make the idea simpler to understand.

I was just trying to make a point. Believe me, I think fish see exactly what we see ... but if they don't, we would still try to "match the hatch" because WHATEVER they see ... never mind.

[SilverCreek 0]

OK, I get it.......... now ;^)

 

Thanks

[JSzymczyk 0]

I'm a firm believer in the science of it all. No doubt the fish's visual response to radiation in the band "xyz" happens. It cannot be argued. I get what you are saying SilverCreek, I understand that completely. My point is that because an individual fish, or an average individual of a population of fish respond to a certain color in a certain way, does not mean with any certainty that what their brain is telling them is the same as what your brain would be telling you given the exact same set of variables.

 

It's only one factor out of a couple billion (maybe more...) variables every time we try to catch a fish. I've thoroughly enjoyed a couple instances on the Yellow Breeches famous water when the stuck-uppeties were nearing apoplexy about MATCHING THE HATCH and I was catching fish on a #8 black woolly worm.

 

In the end, whether or not fish interpret visual stimuli in a way we can understand is irrelevant... NONE of our flies really limitate the insects, baitfish, crustaceans, or other food sources very well yet the fish still hit them.

 

There are some exceptionally talented fishermen who state point blank that color is the least important variable we can control. I don't always agree with that, but sometimes it is true.

[SilverCreek 0]

I'm a firm believer in the science of it all. No doubt the fish's visual response to radiation in the band "xyz" happens. It cannot be argued. I get what you are saying SilverCreek, I understand that completely. My point is that because an individual fish, or an average individual of a population of fish respond to a certain color in a certain way, does not mean with any certainty that what their brain is telling them is the same as what your brain would be telling you given the exact same set of variables.

 

It's only one factor out of a couple billion (maybe more...) variables every time we try to catch a fish. I've thoroughly enjoyed a couple instances on the Yellow Breeches famous water when the stuck-uppeties were nearing apoplexy about MATCHING THE HATCH and I was catching fish on a #8 black woolly worm.

 

In the end, whether or not fish interpret visual stimuli in a way we can understand is irrelevant... NONE of our flies really limitate the insects, baitfish, crustaceans, or other food sources very well yet the fish still hit them.

 

There are some exceptionally talented fishermen who state point blank that color is the least important variable we can control. I don't always agree with that, but sometimes it is true.

 

There are at least three issues I see you discuss. The first is that fish hit our imitations although the imitations are imperfect according to WHAT you as a HUMAN sees. Trout have very poor vision. It is 14 times worse than human vision. An eagle can see a rabbit from a mile away. Yet by comparison, an eagle's vision is "only" 12 times better than human vision. This relative comparison of the vision of an eagle to a human and humans to trout means by comparison to human vision a trout is legally blind.

 

So the fact is that trout cannot see things very well so that is one reason that our imitations work. The flies may not look like good imitations to you, but a trout cannot see the details so they look close enough.

 

The seminal article on trout vision was published by an American ophthalmologist, Gordon Byrnes, MD. It was titled, How Trout See: volume 21, issue 5, of Fly Fisherman Magazine, July 1990. pp 56. That article is the work upon which the Sexyloops site and other articles on fish vision have been based. Check out Salmonid Vision at sexyloops.

The second point is that Individual fish are part of a population, so population dynamics apply when we speak about the behavior of a population of trout instead of individual trout.

 

I discussed how selectivity develops in trout populations in the post below:

 

http://www.theflyfishingforum.com/forums/general-discussion/334575-selectivity-why-how-do-trout-become-selective-feeders.html

 

If you will read the post about selectivity, you will understand why you were catching fish on a wooly bugger during a hatch on the Yellow Breeches. When we fish, we are sampling the population for the fish that are susceptible to the patterns and techniques that we are using. That is what fly fishers do every time we go out. We are doing a scientific population sampling experiment. So the fact that you caught fish on a wooly bugger does not disprove selectivity. What it "proves" is that either the fish were not very selective, or that some fish were not selective, or that there were enough fish so that even if most of them were selective, there would always be fish that are not selective.

 

In terms of selectivity to color, population dynamics also apply. One cannot use a sampling technique that selects a specific subset of the population and then suggest that the sample you catch represents the entire populations. That is the fallacy of hasty generalization.

 

http://www.nizkor.org/features/fallacies/hasty-generalization.html

 

I have discussed the third point before but apparently it needs to be re-emphasized. We do not need to know exactly how color is processed the fish's brain to match color in our patterns. All we need to know is that humans can pick out the color of the prey and match the color in the flies we use. The criticisms of color could be applied to size and shape as well. We don't have to know exactly how size and shape are processed in the fish's brain. Nor do we need to know how prey motion or behavior is processed. All we need to do is to imitate the size, shape, and behavior. If we match size, shape, behavior and color in your imitations, regardless of how that is processed in the fish's brain, we are matching the pattern the fish's brain has for the prey.

 

The argument you are making as to whether we can trust our senses or the trout's senses goes way back in philosophy to Rene Descartes who died in 1690. He did not trust his own senses, and Descartes had to prove to himself that his senses gave him an accurate interpretation of the world. You have expanded that doubt to whether the fish sees what we see. Rene Descartes did not know anything about neuroanatomy and yet Descartes began with doubt to defeat skepticism. I hope in the same way, I have removed some of your doubt that we as humans, can match the hatch without the need to knowing exactly how the fish's brain processes data.

 

http://www.philosophypages.com/hy/4c.htm

 

I am reminded of a true story of a student, who during a phylosophy lecture asked his professor how he (the student) could be sure that he (the student) even existed. The professor, lowered his glasses and said, "And who may I ask, is asking?" The point is that one cannot ask about our own existence without the question affirming our existence.

[mikechell 0]

"Trout have very poor vision. It is 14 times worse than human vision."

Where did you get this piece of data? I've read and heard that their close vision is much better than ours. What we would see at a foot, they can perceive at 4.

The long distance vision is worse (beyond 20 feet), but then, in the water, long distance is not needed.

 

The trout anglers are always talking about the need to tie size 20 to 32 flies because the trout are selectively feeding on insects that small. That doesn't sound like "legally blind" to me ... at ALL.

[heavynets 0]

I agree wth Mike. I've read the same thing and have seen trout grab a tiny nymph in a rapids. That is, I think I saw it. At least I perceived it in that way. Of course it could have been a dream of a dream.

[SilverCreek 0]

"Trout have very poor vision. It is 14 times worse than human vision."

Where did you get this piece of data? I've read and heard that their close vision is much better than ours. What we would see at a foot, they can perceive at 4.

The long distance vision is worse (beyond 20 feet), but then, in the water, long distance is not needed.

 

The trout anglers are always talking about the need to tie size 20 to 32 flies because the trout are selectively feeding on insects that small. That doesn't sound like "legally blind" to me ... at ALL.

This has to do with the visual acuity of the trout. As computer users, we are familiar with pixel count. The higher the pixel density, the clearer the image. For trout and human vision, rod and cones are the equivalence of pixels. The higher the density of these visual elements, the clearer the image. Humans have a macula, which is an area of high resolution vision and dense concentration of cones. Trout do not.

A trout has the rods and cones relatively evenly distributed over it's retina. As noted above, humans have a concentration of receptors in the fovea at the center of the macula of the retina so we can see great detail when focused on an object. A trout sees everything at the same detail and it cannot see an object better by centering its vision on it.

We see 14 times better than a trout because we have 14 times the density of rods and cones in our retina. By comparison our vision is relatively better than a trout than an eagle's vision compared to us.

If you had actually checked out my reference in my previous post, you would know where I got the 14 times worse.

Check out Salmonid Vision at sexyloops.

"General vision

It seems that compared to ourselves, trout and salmon have pretty poor vision - in fact compared to the fish, our vision is about 14 times better at resolving images. This is more than a little reassuring to me- it's good to know that even my ageing vision must still be at least 12 times better than theirs!"

A trout has a round lens when compared with a human lens which is more disk shaped. Because the lens of a trout must focus light that enters the lens from water, it needs to be more spherical than a human lens which bends light entering from air. This allows the trout eye have a wide depth of field - IE, the shape of the lens does not need to change much to focus for a specific distance. So to a trout virtually everything is in focus. Humans can focus on a specific object and this allows humans to more easily concentrate their vision on a specific object.

The seminal article on trout vision was published by an American ophthalmologist, Gordon Byrnes, MD. It was titled, How Trout See: volume 21, issue 5, of Fly Fisherman Magazine, July 1990. pp 56. That article is the work upon which the Sexyloops site and other articles on fish vision have been based.

This is how we see a standard dry fly. We can see some of the separate "wing" through flat clear water and overlapping hackle.

Now comes a series of photos showing what the trout sees at increasingly closer distances. The trout sees best at three inches and not any closer.

Here is a trout's view at one foot.

At 6 inches

At three inches. This is as good as it gets for a trout.

Now here is what a real insect looks like to a trout. Compare it to the fly.

Mayfly at 6 inches

Mayfly at 3 inches

The key question is does that fly look like the mayfly?

Thank goodness for the poor vision or we would rarely fool it.

[heavynets 0]

You said, "So to a trout virtually everything is in focus."

 

Gordon Byrnes seems to say that focus changes with distance. Which is it?

[FlaFly 0]

Just got back after two days away. Silver... when did black become a color? Color comes from light (wavelengths). Black is the absence of light. White is a blend of all wavelengths, thus white is a color, black isn't.

[SilverCreek 0]

Just got back after two days away. Silver... when did black become a color? Color comes from light (wavelengths). Black is the absence of light. White is a blend of all wavelengths, thus white is a color, black isn't.

 

 

You are correct that black is the absence of light and is not a color.

[SilverCreek 0]

You said, "So to a trout virtually everything is in focus."

 

Gordon Byrnes seems to say that focus changes with distance. Which is it?

 

Heavynets,

I am not sure what you are referring. Dr. Byrnes says that trout has a long depth of field. On page 57 of the article, Dr. Gordon Byrnes writes, "The eye always remains focused on infinity, looking laterally, backward, down and straight up. When the trout's lens is retracted in a focusing effort, the fish is able to see forward to infinity while the focus of other positions of gaze remains essentially unchanged. In this way the trout may actively focus its eyes only looking forward, while the remainder of the visual field is focused in the distance. Because the lens of the trout eye is very powerful, objects from approximately 6 feet and beyond are all in focus on the retina at the same time when the fish gazes at distant objects,”

A trout has a spherical lens that has a long depth of field. Since Dr. Byrnes article, with further research we now know that the depth of field is even greater with objects in focus from 2 feet to infinity and possibly from several inches to infinity. So for a trout "virtually" everything is in focus.

Left is trout lens and iris and right is human.

See this from The Trout and The Fly by Brian Clarke and John Goddard. Also published in Understanding Trout Behavior by John Goddard and Brian Clarke. The trout can focus from 2 feet to infinity.

r

https://books.google.com/books?id=V8BpCd70c18C&pg=PA66&lpg=PA66&dq=trout+vision+depth+of+field&source=bl&ots=vIoKlFSDGk&sig=UrVkPvN9Dm92V4sO151nXhKPe-o&hl=en&sa=X&ved=0CDgQ6AEwBWoVChMIzqW6z_C4yAIVQhYeCh258ge3#v=onepage&q=trout%20vision%20depth%20of%20field&f=false

https://books.google.com/books?id=ZaqO1wDJHi8C&pg=PA94&lpg=PA94&dq=trout+vision+depth+of+field&source=bl&ots=8TTuCIfreh&sig=PpX3PxvbyKc4Cv4g5PEIFBLbuCo&hl=en&sa=X&ved=0CBwQ6AEwADgKahUKEwixuY289bjIAhVHlA0KHQTOAHA#v=onepage&q=trout%20vision%20depth%20of%20field&f=false

See the quote below from Prospecting for Trout by Tom Rosenbauer.

”When focusing on an object 2 feet away, a trout sees clearly to infinity, at to the limits of the physical properties of water and air.”

https://books.google.com/books?id=sQBnAQAAQBAJ&pg=PA8&lpg=PA8&dq=trout+vision+depth+of+field&source=bl&ots=Y3Q-dhTJTA&sig=A86CPVtIl2RIzNc7J9-_Dh52Sr4&hl=en&sa=X&ved=0CC8Q6AEwA2oVChMIr7Kv2MO4yAIVQ5ENCh2AUgaA#v=onepage&q=trout%20vision%20depth%20of%20field&f=false

For closer than 2 feet the trout moves the position of the lens rather than change the shape of the lens as humans do. A trout is able to move its lens to focus closer than we can change the shape of our lens to focus close. So a trout can focus closer. That is why Mikechell said, "I've read and heard that their close vision is much better than ours." A trout's vision is NOT better than ours, but it can focus closer than humans. But at that closer focus, a trout still has poor visual acuity (pixel count) compared to the high pixel count of the macula of the human retina.