Discussion Of "the Raptor Effect" By Dr. Howard Wright 2024
Bassun reply :
Hello all -- I wanted to hear thoughts and comments surrounding the article Dr. Wright posted as well as offer a counter theory which I feel is more impactuful in terms of fish relating to a floating dock.
First, let me clearly define that this is NOT a troll post or anything of that nature. I do, however, have some differing opinions on his theory. However, I would also like to clarify that I do not completely dismiss his theory on the fishes preservation instinct completely. It is my opinion that there are other factors beyond age old preservation which often time places bass under floating docks, and other hard surface cover.
To begin, I would like to expand on the temperature concept. I absolutely agree that the water under a dock, generally, is not noticeably cooler than the surrounding water. Given waters physical properties and what we understand of the physics of the motion of water, as well as the thermodynamics of water it makes complete sense that a small dock covering a miniscule area of water would have only the most negligible effect on water temps. Although I agree that the water itself is not significantly warmer, we do know that sunlight heats water and the intensity of that light is rapidly diminishing as studies present that less than half of the surface intensity is present at only three feet. These figures obviously change depending on the specific water conditions. The more clear the sample water the deeper the penetration will be, and conversely muddy or deeply stained water will be much more capable of stopping the light. Over 25% of surface light is incapable of penetrating even over 1 centimeter!
Focusing on the fact that there is a radiant intensity at three feet (and deeper), we know there is an ability for heat to be recognized. While the water itself may not have a discernible temperature variation, any objects resting within this "radiant zone" will be capable of absorbing the heat. So, I postulate that an object at rest is capable of absorbing heat from the sun at a greater rate than the surrounding moving and highly thermally conductive water, especially if that object is dark colored. Given, the fact that it is surrounded by water does help negate the impact as well as the actual depth of said object noting a very quick reduction of intensity of light in water.
Now having said all of that, do I believe that is the primary reason for fish under cover, no -- but to completely ignore the radiant impact of the sun is a bit dismissive. Obviously, depth change is much more effective and has other benefits and thusly I would suggest if a fish did want to cool down, it would just go to a deeper depth usually. But, I do not think we can completely ignore the thermal impact of sunlight penetrating the surface.
I could be wrong, but that's how I understand it. Now, given that, even I do not believe that is the main reason for fish in shady areas. I do, however, believe there is more to it than just the Raptor Effect. Let us consider vision, not of birds of prey, but of the fish. Fish eyes are very similar, in most cases, to human eyes. Now, let's consider a scenario of varying light intensities in which we should be familiar with, then apply those scenarios to fish.
If you have ever been inside your house, looking out at night you have probably noticed a couple of things. A: It's difficult to see outside when it is bright inside, and dark outside. B: Easy to see when it is dark inside, and a light is on outside. Considering that bass are predatory, largely sight based feeders, it becomes evident they would naturally select a situation where they can more easily see. We know, from our own experience, it is easier to see from a darker location looking into a well lit area.
Expanding the effects of light on vision, we should also consider light blindness. Not as in permanent or even flash blindness where the retinal pigments are bleached out; but rather the scenario where you have sunlight hitting your eye directly, and you are trying to see. I'm doing a poor job of describing the situation - consider the following. You are standing in the sun with no hat, and the sun is hitting you in the face. Naturally you will squint, then probably put a hand up to block the sun from directly hitting your eyes, and eventually probably put on a hat and sunglasses. With each of these additional shading techniques you will note that your ability to see increases. A better example is when you are driving into the sun. You are often "blinded" by the light, and will lower a visor to block the sun.
Now considering most fish can't squint, cover their eyes with a hand (Chernobyl maybe? lol) or wear hats, but have the same impacts on their vision, it stands to reason they are likely to migrate to a location where the intensity of the sun is reduced, aka shade. One of the more significant differences in a fishes eye vs human is the way our pupils work. Most fish have fixed pupil sizes. Whereas a humans eye can reduce the glare of light by decreasing the amount of light passing in by reducing the pupil size a fish usually cannot. Their eyes do adjust to different levels of light, however, it is accomplished utilizing a shift in the relative location of the rods and cones in their eyes. This is a much slower process and depending on the fish may take up to an hour for a major shift to occur.
Certainly, beyond being able to see, we should also consider being able to be seen - but not just from above but from prey. A fish silhouetted in bright open water is much easier to see then one hiding in the shadows both from above and below the surface. I don't think there is any need to develop this any further as we all know bass are ambush predators and are obviously keen at utilizing structure and cover to hide themselves. Everything about a bass is designed for ambushing from cover.
So, in conclusion, I would postulate that a bigger reason for fish staying under the surface cover of a floating dock is related to the fishes sight rather than that of being seen by raptors. I think I have demonstrated multiple positive benefits, related to vision, and considering bass are primarily sight based predators (granted they do utilize all other senses and especially use the lateral line), those benefits would likely be high on their priority list. I absolutly do not feel that this is the only reason a fish relates to cover, rather just one area which in this situation I felt needed to be expounded on.
There is much more discussion to be had surrounding light and water. I did not delve into color spectrum which is visible at different depths or the impact of UV or polarized light. I think all of these play a hugely important role in the life any sight oriented fish.
Lastly, I would like to reiterate that I am not attempting to bash Dr. Wrights article. I found it to be quite interesting and the notion of the Raptor Effect, I think does have some merit. The innate behavior to hide from prey is absolutely a valid and salient fact, it is the level of impact in which I am challenging. I am not a freshwater biologist, so it is possible my theories and conclusions are completely misguided; but I felt inclined to dive a little deeper into this and to at least explore the sight related aspect to fish holding under floating cover.
SHaugh reply :
Any diver will confirm that you can get sunburn underwater.... you need to be several feet underwater before you won't.
Team9nine reply :
This subject has actually been studied rather extensively in fishes, both freshwater and salt water. The penchant of fishes to use shade being a pretty universal behavior. As such, the answer like most things in life, is not so cut and dried, as the research shows that it depends on whether you are the predator or the prey, solitary or in a group, or are more active during daylight or at night. All that said, the generally established conclusions are that light and shading is the most common reason fish use such objects as docks, either to hide from a (water based) predator or to use shade to your predatory advantage. I would have to believe this is the primary reason for such use by bass, especially adult bass. However, the research also suggests that for some fish (bluegills, etc., and I might assume to some degree even small bass), reared in a hatchery environment and later stocked into lakes, that the "raptor effect" is likely a very real behavioral response.
-T9
Swampstud reply :
Imo they like the shade or dark areas because it covers there outline/silouette. Your right about it bein difficult to see with the sunlight in your eyes. Now remember how bass utilize "edges" , that shadeline is a prime edge. The bluegill thats swimmin out around the dock right near that edge, hes got the sunlight in his eyes at some sort of angle. Shear disadvantage.
Now that bass sittin in the dark with no outline, maybe a blur of green n white is lookin out into that lit up area right infront the dock. The sun highlighting every twitch an kick of the bluegills tailfin. That bass is utilizing a prime peice of cover an a seeking that perfect feeding oppurtunity. Complete advantage for mr.bigmouth
Ive seen it a few times on hook n look.
Theyll use a clump of grass, stump, treetop in the same manner. Something to cover up that outline to keep from being spotted.
As a bowhunter we ALWAYS are searching for a tree thats got plenty of cover to prevent the deer from siloutting us.
Paul Roberts reply :
On 10/9/2014 at 3:16 AM, Bassun said:... we all know bass are ambush predators and are obviously keen at utilizing structure and cover to hide themselves. Everything about a bass is designed for ambushing from cover.
First of all, bass are not "ambush predators". They are not built like ambush specialists that use a very high degree of camouflage, and an entirely sedentary hunting behavior. Some even lure prey to themselves. Examples of true ambush predators are stonefishes, scorpionfishes, flatfishes, and various bathypelagic species that hunt in complete darkness.
Bass are not specialized pursuit hunters, stalkers, or habituaters either. They are "generalists" using all of these strategies and more. What I believe we are seeing when bass are "ambushing" (OK if used very loosely) are fish at a low activity level and resting. Bass are opportunists and will take a lure or prey that blunders too close, even when the bass are in an energy conservative state. Realize that prey doesn’t “blunder too close” all that often hence, in part, the need for both energy conservation and the more active hunting states. Energy conservation tends to be done where they are safest -under cover, and near or over deep water. What I believe Dr. Wright saw, when viewing those bass under that floating dock away from any other cover, were simply resting bass.
"Radiant effect" is plausible. I always wanted to test that.
We can't, and I know you didn't, preclude the raptor effect as part of the story. I fish small waters -a lot of them- and aerial threats such as kingfishers, herons, terns, osprey, and eagles are a nearly constant threat. Google any one of these birds along with "bass" and you'll see a lot of images people just happened to capture. Aerial threats create an instantaneous instinctive response from fish -especially so on sunny days. I've watched carp, bluegills, and bass bolt under passing light aircraft (500feet up!). Ever try to throw a lure over shallow fish under bright skies? Aerial threats are well understood by fish.
Underwater threats are real too. This could be remembered or immediate. Bass are prey for much of their (often short) lives. Everything eats bass fry. Later, larger bass, pickeral, pike, crappie, catfish, and muskie are threats. Then there are mammals. I see mink on my ponds and once saw one pop to the surface with a 10inch bass. There was a time when otters were MUCH more common than they are now.
No, predation is not the whole story and all your points are good ones. Thermoregulation (possibly) and energetic states are likely part of the story as well.
Bassun reply :
On 10/9/2014 at 8:18 AM, Paul Roberts said:First of all, bass are not "ambush predators". They are not built like ambush specialists that use a very high degree of camouflage, and an entirely sedentary hunting behavior. Some even lure prey to themselves. Examples of true ambush predators are stonefishes, scorpionfishes, flatfishes, and various bathypelagic species that hunt in complete darkness.
Bass are not specialized pursuit hunters, stalkers, or habituaters either. They are "generalists" using all of these strategies and more. What I believe we are seeing when bass are "ambushing" (OK if used very loosely) are fish at a low activity level and resting. Bass are opportunists and will take a lure or prey that blunders too close, even when the bass are in an energy conservative state. Realize that prey doesn’t “blunder too close” all that often hence, in part, the need for both energy conservation and the more active hunting states. Energy conservation tends to be done where they are safest -under cover, and near or over deep water. What I believe Dr. Wright saw, when viewing those bass under that floating dock away from any other cover, were simply resting bass.
Paul -- You are absolutely correct, and I was too cavalier with my declaration as ambush predators in the purest sense. Given the discussion level, I should have thought more about that statement. I was simply meaning to convey they are designed for success in and around cover vs scavaging or hunting large expanses of open water, etc. Their bodies are designed for short powerful bursts of speed, and they will utilize structure and cover to feed from. Your description as "generalists" and "opportunistic" is a much better description and much better conveys their feeding methods.
Thank you for correcting that and adding a good description of their feeding habits.
On 10/9/2014 at 5:13 AM, Swampstud said:Imo they like the shade or dark areas because it covers there outline/silouette. Your right about it bein difficult to see with the sunlight in your eyes. Now remember how bass utilize "edges" , that shadeline is a prime edge. The bluegill thats swimmin out around the dock right near that edge, hes got the sunlight in his eyes at some sort of angle. Shear disadvantage.
Now that bass sittin in the dark with no outline, maybe a blur of green n white is lookin out into that lit up area right infront the dock. The sun highlighting every twitch an kick of the bluegills tailfin. That bass is utilizing a prime peice of cover an a seeking that perfect feeding oppurtunity. Complete advantage for mr.bigmouth
Ive seen it a few times on hook n look.
Theyll use a clump of grass, stump, treetop in the same manner. Something to cover up that outline to keep from being spotted.
As a bowhunter we ALWAYS are searching for a tree thats got plenty of cover to prevent the deer from siloutting us.
Swampstud -- what a great description of fish feeding from dark to light. While not "ambush" in the sense a stonefish ambushes, this is more akin to what I was trying to convey. You hit it spot on, and comparing it to bow hunting makes perfect sense. You are literally trying to do the same thing, and would never find good success without good cover. Excellent points.
On 10/9/2014 at 4:54 AM, Team9nine said:This subject has actually been studied rather extensively in fishes, both freshwater and salt water. The penchant of fishes to use shade being a pretty universal behavior. As such, the answer like most things in life, is not so cut and dried, as the research shows that it depends on whether you are the predator or the prey, solitary or in a group, or are more active during daylight or at night. All that said, the generally established conclusions are that light and shading is the most common reason fish use such objects as docks, either to hide from a (water based) predator or to use shade to your predatory advantage. I would have to believe this is the primary reason for such use by bass, especially adult bass. However, the research also suggests that for some fish (bluegills, etc., and I might assume to some degree even small bass), reared in a hatchery environment and later stocked into lakes, that the "raptor effect" is likely a very real behavioral response.
-T9
Team9nine - Perhaps I should have researched and referenced that information vs posing my own suppositions, but it's good to hear my thought process and understanding isn't devoid of proven fact. And I absolutely agree that there are TONS of other factors which should be considered. And surely there is merit to the raptor effect.
All said, perhaps I am being too dismissive and potentially being too locked into the singular reasoning given in the article. I'm sure Dr. Wright had not intended to pose that the "only" reason is the raptor effect.
I should also consider the locale and types of raptors in the population. I think truely one would need to consider a least a few factors to effectively suggest the raptor effect as a primary reason for use of open cover. The number of birds of prey vs the amount of available prey outside of water would certianly be a contributing factor. If you are in an area with a high density of predators, and a low level of mammalian prey then it would seem likely fish would be a higher staple regardless of the raptor. In the same sense, water predators like eagles and osprey are absolutely going to target fish more often then say a Broad-winged or Red-tailed Hawks.
Locally, we have a higher density of non-fishing raptors - I think that has somewhat jaded my notion of the raptor effect. (South-Western VA) I suspect, someone in an area with a greater density of fishing birds would be more likely to be impacted by the raptor effect. My suspicion is that Dr Wright is in an area such as that, and given those factors his conclusion certainly holds a greater merit. Locally, I've only seen the smallest fish taken by any birds. But, our density of Osprey and Eagle is fairly low where as our Hawk density is much higher. The fish I personally have seen taken mostly come from Great Blue Herons and I have never personally seen an Eagle take any fish from the local waters. That's not to say they don't, only that it is something I have not personally witnessed.
Thanks for the conversation y'all. This article has certainly opened up an interesting conversation, and I think legitimatly offers another reason for the positioning of bass.
bighed reply :
Wow dude, that would have taken me three days to formulate and write! As far as birds of prey, bass in this area will rarely encounter an eagle or osprey. They do however encounter comorants constantly and overhead cover does little to protect them from these birds. The tell tail V mark on the backs of bass have become so prevalant it's very rare that a trip to the lake doesn't produce a fish with that scare. However, the bass still do relate to docks I believe for the reasons you explained.
Bassun reply :
lol sometimes I get to rambling...
We don't have any perminate populate of cormorant's here, at least as far as I know. Have you noticed any difference in how the bass react when there is a cormorant on the water? I'm curious if they tend to get defensive and hole up or if they continue to hit and feed as normal?
bighed reply :
The comorants are pretty easily spooked where I fish. They do not hang around when a boat approaches so it's a little hard to say if their presence affects the bite. It does seem that a bass will bite as soon as the bird is run off by an approaching angler so I would say the fish are not leaving the area.
roadwarrior reply :
WOW!
Very interesting discussion.
Dwight Hottle reply :
On 10/9/2014 at 9:24 PM, bighead said:The comorants are pretty easily spooked where I fish. They do not hang around when a boat approaches so it's a little hard to say if their presence affects the bite. It does seem that a bass will bite as soon as the bird is run off by an approaching angler so I would say the fish are not leaving the area.
I agree with that observation completely. Here on lake erie the cormorants are boat wary & leave the area.
I have observed the exact opposite down off SW Florida in the gulf. Down there I have seen cormorants hanging around boats like pelicans waiting for undersized or catch & release fish like sea trout. You could release a small trout on the port side of the boat & see the cormorants swim up on the starboard side surface & swallow the fish you just released. It must be a learned behaviour.
SHaugh reply :
If fish are overly concerned with remaining hidden from overhead predators why do they approach lighted areas at night ?
While I'm sure there is an instinctive avoidance mechanism toward this type of predation, I don't think it explains the behavior very well. Does a fish need to worry about a crane or heron in 6 feet of water ? Yet we all know that they will still migrate toward the deep shade even on a floating dock out in 20 feet of water.
I think you are much more on the right track when you talk about UV radiation and how fishes eyes work. They are very sensitive but slow to adapt to changing light levels. the kind of sharp contrasts that occur in a sunny shallow environment are exactly what they would want to avoid. If their eyes are adjusted to some level of very bright sunlight, then shaded areas must appear very black and unknown to them. For this reason they would seek out the middle ground because that is simply where their eyes function best and have the greatest range of visual adjustment.
Their sensitive eyes are undoubtedly affected by UV exposure as well... they probably get "sore" when they spend too much time in direct sun.... As I said about sunburn above, most organisms are not 100% adapted to full sun exposure, and will avoid it when possible.
If you observe natural design and evolution you will quickly notice that nature abhors excess capacity. Organs like eyes are simply not designed to be very robust at the extremes of their requirements. This is what allows the organ to function well through a broader range of conditions. If I want to design an eye to see well in the dark, it is a given that it will not work so well in bright sunlight. I think this train of thought goes a lot further in explaining why fish prefer the "middle ground" of their environment.
Another analogy would be how humans design a building that they will inhabit. What temperature do they select ? What light level ? Etc. We choose to occupy areas that are most "comfortable" to us.
Choporoz reply :
Fascinating discussion!! Everything you've written Bassun makes sense to me. Unfortunately, every time I read more about bass instincts and tendencies, I manage to amuse myself to the point of distraction.....I want to know what the bass was thinking!....but, really....who the heck is ever going to know what a fish was thinking....what was I thinking....lol
I'd like to coax the discussion towards a little more empirical aspects.
Are bass as likely to gravitate towards the underside of dock if it is cloudy? What about at night?
Team9nine reply :
On 10/9/2014 at 11:58 PM, Choporoz said:I'd like to coax the discussion towards a little more empirical aspects.
Are bass as likely to gravitate towards the underside of dock if it is cloudy? What about at night?
While those conditions don't preclude bass from using such structures for a variety of reasons, on cloudy days and at night, the relative visual advantages offered by them (docks) on brighter days are decreased considerably, and hence studies have shown a corresponding decrease in the attractiveness of such overhead objects. It's been suggested that bass and similar predators are actually more likely to move down and away in the water column to be better able to silhouette prey against a potentially lighter background (sky) at night, as well as to use a "flushing" behavior (Doug Hannon, John Hope) during active low light feeding periods (see: http://www.bassresource.com/fish_biology/ambush_bass.html).
-T9
bighed reply :
No doubt in my mind that the bass do not hug as tightly to a dock on a cloudy day as a sunny one. Also, for me, dock fishing is something that I don't start doing until the sun is high. The later in the day the more bass will load up in the shade of a dock
WRB reply :
I haven't read the referenced article "the raptor effect" and will commit later.
What sentence the caught my eye was bass eyes are like humans, not true. The fact is we don't know how bass see. There are lots of assumptions based on eye constructions for example Dr Keith Jones.
Keep in mind a simple fact; bass have evolved as a sight feeding predator living underwater and have developed keen senses to work as a system to located prey like lateral line nerves, hearing, odors, etc.
What has been written to date doesn't explain how bass see in the dark, low light or very bright light in clear water. Having caught bass in all those conditions over a 60 year period, my experiences are not answered by current science. I believe bass have far better color vision and low light vision than a human. Slight changes in color can make a big difference in total darkness or very bright clear water.
Water wave action defuses light and creates light movement that acts to camouflage bass to their prey.
In regards to water temperature variations within the water column consider water density layers and current.
It would be nice if folks simply swam in the lake they fish, water temperature isn't homogenous, it's both warmer and cooler same areas within an area is common.
All cover isn't equal, aquatic green vegetation produces dissolved oxygen a key factor for bass. The cover aids prey seeking sanctuary from predators like bass and food, both reasons bass use cover areas.
Tom
tatertester reply :
A few seasons ago I was fishing an area of the lake that was a large expanse of mixed surface weeds. The water surface was flat and I was casting a frog. I made a long cast that got away from me and ended up being a very high lob cast. I was watching to see where the frog would end up landing. Much to my surprise, as the frog passed overhead along the water surface , many fish ,along the entire path of the lure ,created a disturbance in the water until the frog landed......I couldnt believe what I had just seen...Fish obviously reacting to the overhead lure, along the entire path of the bait....The whole thing was impressive.I couldnt believe how many fish were in that slice of water.
SHaugh reply :
I agree that we should not imagine how a fish sees by imagining a human underwater with a mask on. One of the key differences between men and fish is that a fish has an extremely large and upward facing field of view. They also don't have necks which allow humans to angle their eyes away from strong light sources.
So imagining a fishes world I believe that when the sun is high in the sky their eyes are literally being overloaded with direct sunlight.. and there is no way for them to squint or avoid it... similar to if you were forced to turn your face upward directly toward the sun and then attempt to open your eyes and see what is in front of you. Naturally your vision would be seriously compromised by all that direct sunlight flowing into your eye.
This would compel you to find places where that bright overhead sun was not directly shining in your eyes.
Bassun reply :
On 10/10/2014 at 6:30 AM, SHaugh said:I agree that we should not imagine how a fish sees by imagining a human underwater with a mask on. One of the key differences between men and fish is that a fish has an extremely large and upward facing field of view. They also don't have necks which allow humans to angle their eyes away from strong light sources.
So imagining a fishes world I believe that when the sun is high in the sky their eyes are literally being overloaded with direct sunlight.. and there is no way for them to squint or avoid it... similar to if you were forced to turn your face upward directly toward the sun and then attempt to open your eyes and see what is in front of you. Naturally your vision would be seriously compromised by all that direct sunlight flowing into your eye.
This would compel you to find places where that bright overhead sun was not directly shining in your eyes.
I think your assertion that this would compel fish to "shade" their eyes is spot on.
On 10/10/2014 at 2:38 AM, WRB said:I haven't read the referenced article "the raptor effect" and will commit later.
What sentence the caught my eye was bass eyes are like humans, not true. The fact is we don't know how bass see. There are lots of assumptions based on eye constructions for example Dr Keith Jones.
Keep in mind a simple fact; bass have evolved as a sight feeding predator living underwater and have developed keen senses to work as a system to located prey like lateral line nerves, hearing, odors, etc.
What has been written to date doesn't explain how bass see in the dark, low light or very bright light in clear water. Having caught bass in all those conditions over a 60 year period, my experiences are not answered by current science. I believe bass have far better color vision and low light vision than a human. Slight changes in color can make a big difference in total darkness or very bright clear water.
I agree with some of your points, but have to completely disagree in regards to the similarities of the eye. I also agree there is not tons of research about the eyesight of bass specifically, but I believe we can actually say that functionally the eyes are quite similar.
Comparing the two you have the same basic structure: lens, cornea, iris, pupil, retina and so forth. Fish eyes also have rods and cones just as human eyes do. The eyes work, generally, to the same end. Some of the specific methods are different, but the overall design and function is quite similar.
Some of the more notable differences would be: a much-expanded monocular vision, how the lenses adjust, and how they regulate photic conditions. Expanding on a few of the notable differences, but certainly not to be considered all inclusive, I think we can explore some of the structural differences.
Let’s start with the lens. In a human eye our lens is flexed and relaxed in order to adjust focus. A bass lens is comparatively larger and shaped more round versus the convex shape of a human lens. Given the shape, it stands to reason that flexing would not be the method used to change focus – rather a retractor muscle adjusts the positioning to create focus.
An added benefit of the round lens is that it allows for correction of spherical aberration, which ultimately leads to fish being able to focus any available light very sharply.
Now the Iris and Pupil work differently as well. And while there are a variety of pupil types in fish, some such as shark are even capable contraction and dilation to control the amount of light entering the eye, bass do not have quickly changing pupil sizes. It was mentioned earlier that bass are quite slow to adjust from light to dark vision. The reason for this is that they simply do not dilate their pupils and allow more light in or contract them to restrict light; rather they use retinomotor activity, a change in the positioning and ratio of rods and cones effectively active, as well as their pigment proportions, in the eye to control the sensitivity to light.
Obviously I am just glazing the surface on some of the more complicated differences in our eyes, but as a whole they are quite similar. They have a pupil to let light in, focus that light with a lens on the retina, and the optic never carries the signals to the optic lobe in their brain. There has been a lot of research on fish vision, although not as much specific to bass only. Admittedly, I have not done the research myself, and am just referencing others work.
Now I would have to agree things are based on assumptions, but realistically how can we have any empirical data on exactly how a fishes brain decodes the nerve signals.
geo g reply :
Wow a lot of thought went into all the answers. I don't think its so much of a bird of pray thing but simply a sunglass effect. With bright skies, we put on a hat and sunglasses seeking shade and eye relief. Fish seek shade in thick cover, and structure like docks. In early morning the fish are often scattered and away from the tight cover. As the sun gets high in the sky, bass will often seek out shade and relief from the intense sun. In Florida we have many birds of pray that seek out fish. To me I don't see that as a big factor. Just like us, bass seek eye relief from the intense rays of the tropical sun, and sunglasses are just too dam expensive! 
Paul Roberts reply :
On 10/10/2014 at 2:38 AM, WRB said:...
What has been written to date doesn't explain how bass see in the dark, low light or very bright light in clear water. Having caught bass in all those conditions over a 60 year period, my experiences are not answered by current science. I believe bass have far better color vision and low light vision than a human. ...
There is a fair amount of research on night activity and hunting success at various light intensities, as well as turbidity. My take-home is that mature bass see quite well in dim light -are even adapted to it. It takes some time to adapt after nightfall (as it does for humans). That hunting success rates fall as lighting approaches complete darkness. And that the lateral line system becomes more important in very low light and as turbidity increases.
On 10/10/2014 at 6:30 AM, SHaugh said:...So imagining a fishes world I believe that when the sun is high in the sky their eyes are literally being overloaded with direct sunlight. ...
I've often fished to bass under brilliant skies and clear water. They don't seem to mind being exposed at times, and the light certainly doesn't appear to bother their eyes. But, they can be darn tough to catch, able to scrutinize every stupid move my baits make!
That said, there is plenty of research documenting deleterious effects of UV to fish and fish eggs and larvae. UV is a plausible part of the story too.
Brian6428 reply :
What's your line of work, Bassun? Just curious. Great discussion, by the way.
WRB reply :
Explain to me how bass see detail color variances in the dark or very low light conditions at 45' to 60' depths.
Anyone who has tournament fished our SoCal lakes year around will understand how very important color on soft plastics can be.
You can be fishing a 4 1/2" straight tail worm at 40' to 60' and only 1 specific color combination will catch bass, this happens year after year, tournament after tournament....you don't have the hot color you are donating your money. I have given my partner a hot worm and they instantly start catching bass and have been on the receiving end of this exchange. Same everything, location, depth, line, hooks, speed and presentation.
I also tie some very special hair jigs with multiple colors of dyed deer hair combined with custom dyed pork trailers. Some of these jigs have a few strands of flash to add reflective color. Fishing night tournaments in darkness bass will prefer a jig with or without the flash strands and it can make the difference between a good limit and being blanked. The human eye can't see color without the aid of good light, we see shades of gray without light.
Our deep structured lakes have clear water with very good depth of light that averages about 10' and up to 25'. The bass in these lakes have keen eye sight.
The SoCal lakes have very little surface vegetation or weed mats and very little aquatic vegetation for about 10 months of the year. The lakes do not have any boat docks except at the marina, therefor the bass are exposed to predator birds the majority of the lives. We have osprey, eagle, gulls, herons, cormorants, grebes, etc that prey on baby bass to adult bass. No cover, no problem the learn to survive or they don't.
Tom
Paul Roberts reply :
On 10/10/2014 at 10:05 AM, WRB said:Explain to me how bass see detail color variances in the dark or very low light conditions at 45' to 60' depths.
...
They don't.
I guess I've seen too many color theories just not hold up. Here's a fun one:
Kevin Van Dam relates a story in one of his books" (paraphrased):
Four top pros were sharing a large main lake point, and catching bass on worms. Each found a particular color that drew the most strikes. "The only one that worked", they each said when it was over. Interesting thing was, all four ended up "divining" 4 entirely different colors.
WRB reply :
Bill Murphy wrote in his book about a night fishing experience he had regarding a night tournament.
The bite was very slow, he reached in a bag of his worms thinking it was the Otay Special chocolate brown with black blood vain that he was using. Bill instantly started to catch good size bass, handed his partner a worm and he caught another good bass. The worm bag only had a few worms in it and when they were gone he got out another bad of Otay Specials and the bite stooped. Bill picked up one of the torn up worms and looked at it with a flash light, it wasn't the Otay Special that caught the bass, it was a chocolate brown with neon blue vain worm, same size, same make, slightly different color. Found another bag of the neon blue blood vain and the bite returned.
I can't tell you how many times that has happened to me over the years where worm color was critical.
I have also experienced were size was important, color secondary.
Our eyes can only determine color spectrum our brain can interpret, same with fish.
Keep an open mind when it comes to what bass see, it's far different then a human.
Tom
Paul Roberts reply :
On 10/10/2014 at 2:44 AM, tatertester said:A few seasons ago I was fishing an area of the lake that was a large expanse of mixed surface weeds. The water surface was flat and I was casting a frog. I made a long cast that got away from me and ended up being a very high lob cast. I was watching to see where the frog would end up landing. Much to my surprise, as the frog passed overhead along the water surface , many fish ,along the entire path of the lure ,created a disturbance in the water until the frog landed......I couldnt believe what I had just seen...Fish obviously reacting to the overhead lure, along the entire path of the bait....The whole thing was impressive.I couldnt believe how many fish were in that slice of water.
This is WAY more common than many anglers might think. A standard summer day in CO starts with brilliant sun, then giving way to overcast as thunderheads develop. Nearly every day I get to fish under brilliant blue and deep overcast. In shallow water especially, under high vis conditions, the path between us and our lure is made devoid of fish on every cast because of what you just described. Or is our difficulty catching just that the fish aren't biting under those conditions, even asleep?
Well, I've proved to myself that some of those fish are catchable, and I don't have to go to heavy cover to do it. Granted it's not easy to do, and hardly worth the exercise, but it's been worth it just to know. With a long rod I'd make very high casts with a white SB beyond the fish. I choose white to camouflage it against the sky. I then have to keep the line off the water as the line landing on or cutting the water surface turns the fish inside out. But, the SB bulged under the surface works! They'll hit it. Another way, if the shoreline allowed, was to cast long well off to one side and then run the shoreline until the fish were in line with my retrieve. Bang! Fish on, under "impossible" conditions.
Complete opposite of this is when the clouds roll in dense, and the water is dark and calm. I throw a bait and the wakes shoot toward the flying lure, rather than away, the bass often hitting at splashdown. Lighting matters -a lot.
Paul Roberts reply :
On 10/9/2014 at 12:27 PM, Bassun said:...they are designed for success in and around cover vs scavaging or hunting large expanses of open water, etc. Their bodies are designed for short powerful bursts of speed, and they will utilize structure and cover to feed from.
True, but I'd change one word; I'd change "feed from" to feed off. Bass may "ambush" from cover, but I believe this is more about opportunism than a hunting strategy bass are specifically adapted to. Their default hunting strategy is opportunistic cruising, flushing or looking for prey that is vulnerable or otherwise in a compromised position. Bass use terrain (and lots of other stuff –other bass being a particularly important one) to their advantage. This is where their true talents lie. They hunt within, amongst, and off of terrain as much as -or I would argue, more than- from terrain. Hunting in this way makes them effective not only around cover but just about anywhere they can find prey in an awkward spot. Bass even effectively hunt shad and alewives in open water, far away from "cover".
Sky and water conditions weigh in heavy for multiple reasons, not the least of which is that prey is more difficult to approach in high vis conditions and bass hunting success declines in accordance. More bass are apt to be resting, often under cover, during these periods.
But this isn’t the only reason bass head for cover under bright conditions, and bass may not be all resting either. Some are driven to cover under bright conditions because of their increased exposure to predators (raptor effect), and likely UV exposure plays some role too. It may also be that the raptor effect holds greater sway with the bass’s prey. Bluegills head to cover under bright conditions and likely the bass meet them there. Bluegills explain midsummer “frog bites” much better than “frogs” do. (And this explains why blow-ups and misses are so common with frog bites too).
My point is that bass aren’t likely heading to cover so they can see better so they can “ambush” prey. Bright skies don’t get into the bass’s eyes like it would for us. In fact, bright sunlight increases visibility underwater tremendously. But the whole food chain responds with a ripple effect –like a chain being shaken from one end.
Bassun reply :
On 10/10/2014 at 9:21 AM, Brian6428 said:What's your line of work, Bassun? Just curious. Great discussion, by the way.
Thanks. I think it's been a fun convo thus far, and it's forced me to think more deeply about aspects of fish and fishing than I have in a while. As for my line of work, it's nothing even remotely related. I am a Software Test Engineer by trade. I dabble in too many things for fun.
On 10/10/2014 at 8:17 AM, geo g said:Wow a lot of thought went into all the answers. I don't think its so much of a bird of pray thing but simply a sunglass effect.
LOL, the sunglass effect. I like it! And I think it is surely part of the equation!
On 10/10/2014 at 10:05 AM, WRB said:Explain to me how bass see detail color variances in the dark or very low light conditions at 45' to 60' depths.
Tom
Tom I’m going to take a stab at this one for fun. Obviously there are theories out there, and I am in no position to effectively apply the scientific method to attempt to prove anything, but based on what we know I would hypothesize the following: (again, complete conjecture and not a tested theory)
So we’re looking at how bass see detail color variances in very low light at depths of 45-60 feet. I did remove “in the dark” as unless one is in a situation of “absolute darkness” there is some amount of light.
First we would need to look at what happens to light as it filters through water. Now, for purposes of this supposition, let’s assume no extreme factors like extreme turbidity, heavily aerated current, extreme temperatures, etc. And that we are utilizing natural light, and only wavelengths we can see. A “best case scenario” if you will.
Studies of color loss at depth give us some of the first clues. Under our good conditions, with the sun high in the sky, we understand that red is the first colors no longer visible (meaning loss of color saturation, and effectively moved into gray scale – not “invisible”). That occurs in around 15 feet of water. The next to fall off is orange at around 30 feet, and we begin to lose yellow at right around 45 feet. That leaves us with greens, purples, and blues. There is some debate, oddly, about hues of purple. Some suggest that much of the wavelength is lost nearly as soon as yellow, while others indicate it is somewhere between yellow and green and some follow the wavelength directly and indicate violets are the last to fade. I think we would legitimately need to consider more factors to delve into the purples, but from what I have read I personally feel they fall off somewhere around 50 feet.
For the purpose of this discussion I will assume the theory that purples fall off around the same depth as yellows, leaving us with blue and green both being visible through the 45-60 foot depths. There’s just one problem with that…we are looking at figures determined with the sun high in the sky on a bight sunny day. The angle of inclination would be severely different, at best, which means we are no longer looking at a completely vertical penetration of light. The wavelengths would be filtered out based on their transmission through water along a straight line, so at a low angle colors which would fade in deeper waters, would become less and less vibrant at much shallower depths since the light is effectively traveling through more water to make it to a specific depth.
What this tells us, in my opinion, is that vibrant colors will be lost at a very shallow depth once the sun is on the horizon. Reds, oranges, yellows (purples?) would all quickly lose their saturation as the water filters the wavelengths, this would obviously be compounded even further considering the low level of light to begin with. However, studies do show that greens and blues can travel a deep distance (hundred to hundreds of feet). So, given that I would firstly propose that blues and greens are going to be the most saturated colors at depth, with blue being the strongest. Considering the target depth of 45-60 feet I am going to focus on only those two colors.
We understand that bass have rods and cones in their eyes. Rods effectively gather light; cones effectively delineate colors. This is a super glazed version of how they work, but this is a post on a forum, not a scientific paper lol. An important note to consider is the work of George Wald who discovered rods are most sensitive to wavelengths around 498 nm. Blue is about 475 nm green is about 510. Now that is a human rod, and I cannot guarantee the exact same wavelength is most sensitive to fish, but from what I have read, it stands to reason that at least a very similar wavelength would be. Now, as further speculation, I suspect a fishes rods are actually more tuned to a slightly lower wavelength, something in the blue spectrum. This is anecdotal, and based purely on experience of blue/black combo colors fished at night.
We also understand how fish utilize rods and cones to deal with different levels of light. During periods of bright light, the rods are shifted back into “dark pigments” to protect them from the intense light, while the cones are shifted to the surface of the retina. This effectively puts the fish in “color mode” and they are able to see a wide range of colors with a great level of detail. Conversely, when there is low light (some suggest less that one foot-candle for optimum rod emergence) rods fully emerge and the focus is no longer delineation of colors, rather gathering of available light.
Given we know that rods are most effective at seeing the 498 nm wavelength (blue-green), anything around that color will become the most visible. Reflective materials would also, obviously, provide higher levels of light as they are reflecting the full spectrum of light available, not just a specific wavelength. It should be noted, however, the color of the water which “clear” has a blue hue, would effectively influence the perceived reflected color. Given this, I would also surmise that reflective materials would be most effective in clear (technically lightly blue) or slightly green waters as there would not only be a total reflection of all available light, but that light would also be “tinted” the color of the water. If that puts it closer to the 498 nm wavelength (or whatever bass technically receive the best) then the rods would be most capable of photoreception effectively allowing the fish to see the reflected light even better.
So, to answer the original question, “Explain to me how bass see detail color variances in the dark or very low light conditions at 45' to 60' depths.” I pose that they largely do not see “color” variances in that scenario. My supposition, given the above info, is that they see most colors in gray-scale during this situation as the wavelengths of most colors would be too muted to see. However, given their rod sensitivity to a specific wavelength, it is most effective to use a mix of blue/green (again whatever wavelength determined) for their eyes to be most receptive of light. Now, in terms of fishing, given all of the above – I would suggest using a blue/green and black color bait for the best visibility to the fish. If conditions are appropriate, adding flash would certainly be a potential advantage.
Why blue and black vs blue and white? Black is the color recognized when all effective light is absorbed, white is when the entire spectrum is reflected. Given the rods are tuned to a specific color, (assuming blue or blue/green) and often water also has a hue of blue (naturally) or a mix of blue/green during many conditions, any white light reflected would naturally be perceived with a blue / green hue. Conversely, black will always be black. The highest contrast would be a mix of the most photoreceptive wavelength and black. I think this is why we often see the best success in low light with a mix of blue and black lures – this is NOT accounting for lures fished above the fish where black becomes an extremely strong solution as it is actually being silhouetted against a slightly lighter sky. I would also add, that any color in the spectrum, although effectively received as a scale of grays, could be a target color. While it may not be the most contrasting, it is plausible that a shade of gray could be a trigger color vs a blue. Obviously, it depends on forage and what the bass are “looking” for.
Now again, this is PURELY SPECULATION, and would need considerable testing to validate my claims. But, I thought it would be a fun exercise to expound upon. I could be completely off…
Bassun reply :
On 10/10/2014 at 1:15 PM, Paul Roberts said:True, but I'd change one word; I'd change "feed from" to feed off. Bass may "ambush" from cover, but I believe this is more about opportunism than a hunting strategy bass are specifically adapted to. Their default hunting strategy is opportunistic cruising, flushing or looking for prey that is vulnerable or otherwise in a compromised position. Bass use terrain (and lots of other stuff –other bass being a particularly important one) to their advantage. This is where their true talents lie. They hunt within, amongst, and off of terrain as much as -or I would argue, more than- from terrain. Hunting in this way makes them effective not only from cover but just about anywhere they can find prey in an awkward spot. Bass even effectively hunt shad and alewives in open water, far away from "cover".
Sky and water conditions weigh in heavy for multiple reasons, not the least of which is that prey is more difficult to approach in high vis conditions and bass hunting success declines in accordance. More bass are apt to be resting, often under cover, during these periods.
But this isn’t the only reason bass head for cover under bright conditions, and bass may not be all resting either. Some are driven to cover under bright conditions because of their increased exposure to predators (raptor effect), and likely UV exposure plays some role too. It may also be that the raptor effect holds greater sway with the bass’s prey. Bluegills head to cover under bright conditions and likely the bass meet them there. Bluegills explain midsummer “frog bites” much better than “frogs” do. (And this explains why blow-ups and misses are so common with frog bites too).
My point is that bass aren’t likely heading to cover so they can see better so they can “ambush” prey. Bright skies don’t get into the bass’s eyes like it would for us. In fact, bright sunlight increases visibility underwater tremendously. But the whole food chain responds with a ripple effect –like a chain being shaken from one end.
I think you may have just swayed me somewhat, again “opportunistic” being the key.
I agree bright light does increase underwater visibility, obviously; but the position of the sun plays a key role as well. Now considering the extreme range of view bass have, I think positioning would be important in such that the bass would ideally position itself to have the best “lighting” available, while not being “blinded” by the same light. Perhaps my perception is wrong, and they have no problems staring into the sun, but given the UVA, UVB, etc associated with that, as well as the flooding of photonic receptors I cannot imagine it has no impact. But, I could just as easily be wrong.
Great thoughts Paul, thanks for sharing!
Paul Roberts reply :
On 10/10/2014 at 1:28 PM, Bassun said:...
I agree bright light does increase underwater visibility, obviously; but the position of the sun plays a key role as well. Now considering the extreme range of view bass have, I think positioning would be important in such that the bass would ideally position itself to have the best “lighting” available, while not being “blinded” by the same light. Perhaps my perception is wrong, and they have no problems staring into the sun, but given the UVA, UVB, etc associated with that, as well as the flooding of photonic receptors I cannot imagine it has no impact. But, I could just as easily be wrong.
Not all that sure they'd need to be "staring into the sun". They can look all around into a well lit landscape around them. Don't picture them staring up at the sky exactly. But I dunno, I've scuba and free-dived, but I'm not built like a bass. If I roll over on my back in a flat calm swimming pool, and lay on the bottom, the sun can be bright. But I literally have to roll over onto my back to see this. Any other orientation and I'm simply looking at the well-lit background -the pool walls and floor. And they are painted white. Even the underside of the water is not difficult to look at. Remember, sunlight attenuates as it passes through water, not just vertically but horizontally too. It's pretty easy to avoid looking directly into the sun's shortest path. Further, any surface ripples greatly increases scatter.
UV light is an issue that affects more than eyes, so it may play a role. There was some interesting research that suggested that UV light affected nest depth and nest success for bluegills. Apparently at least they are aware of UV.
Good topic and good discussion. Thanks for tackling it.
SHaugh reply :
I think it's pretty hard to even imagine what the world looks like through another creatures eyes... I was reading something the other day that a donkey can see all 4 of his feet at the same time... while looking forward.....
I imagine a fishes view of the world has similar scope and that they are unable to avoid having the sun directly in their field of view at some times during the day...
here's an interesting diagram:
http://astarmathsandphysics.com/o-level-physics-notes/o-level-physics-notes-a-fishs-view-of-the-world.html
What this translates into is something like this:
A bright sun in that patch of blue sky would be very uncomfortable I think.
Certainly just like you or I we can function in bright sunlight... oppressive heat or whatever else we need to do to survive, but all creatures desire rest and comfort at certain times and will seek it out when possible...
Bassun reply :
I agree, SHaugh, with the extended FOV a bass has, positioning would be key if they wanted to avoid light. If I remember correctly, the only real blind spots bass have when combining the monocular and binocular fields of view is basically directly below them and a trailing angle directly behind them. It's kind of crazy to imagine how much more they can see just by moving an eye then we can. I guess its a good think I only have to look at my plate to find my food, lol.
Choporoz reply :
On 10/10/2014 at 1:16 PM, Bassun said:As for my line of work, it's nothing even remotely related. I am a Software Test Engineer by trade.
No offense intended, Bassun, but I doubt that I'm not the only one who is NOT surprised that you're an engineer. LOL 
Thanks for the discussion!
Bassun reply :
LOL --- You know I was actually thinking about the same thing when I replied. ..... now "I'm" that guy.... It's all good though, and absolutly no offense taken. 
SHaugh reply :
I guess our engineer genes are showing...
From a fishing aspect I think the fish eye view photo and the diagram can tell us something.
What it tells me is that when the sun is bright overhead I'm going to try to make my presentations below and to the side of the fish.. never directly above.
If you've ever looked upward at the sun from underwater you will notice that the bright halo of light that is created is very large... I'm thinking if my lure goes through that bright halo my chances are slim.
Bassun reply :
I think you're right, as tatertester and Paul both conveyed the same in that casting directly over the fish has a negative impact in which they have personally noticed. I'm not sure that I would focus on being "below" the fish (if I understand what you meant correctly), but certainly coming alongside vs directly from behind would probably yield better results.
I read somewhere that a fishes visual acuity is greatest at roughly 90 degrees. I took that to mean in the lateral monocular vision, so it would stand to reason that a lure presented beside or to the side of the fish would certainly be noticed. They would then utilize their binocular vision upon approach where their depth perception is best to hopefully target and attack your lure. If only it were really that easy to get these critters to hit lol.
Team9nine reply :
The problem, of course, is that most of this color discussion (as has been already stated) is merely speculation. So while fun to discuss, it likely has little relevance to whether or not we each experience successful fishing, witness the differences in personal experiences shared on this forum topic. There is some stuff we do know, provided by detailed examination of the largemouth bass' eye from studies such as the 2002 Kawamura & Kishimoto paper which appears to be the most recent and heavily cited example in literature. From that study we know the following:
- The occurrence of C-response provides direct evidence for the possession of color vision. In this study, therefore, it is concluded that the largemouth bass can discriminate colors.
- The dominant L-response with a maximum at 673nm and three variations in C-responses might indicate a better color analysis at longer wavelengths, implying that the largemouth bass is able to discriminate red better than blue.
- In the largemouth bass, the visual axis is found in the nasal-temporal direction and the near point is 13.5 cm, indicating that sharp image formation is not performed when an object comes closer than 13.5cm from the eyes. This near point is slightly shorter than those of other teleosts.
- The retina of the largemouth bass is specialized to both movement and form perceptions.
Part of the problem is that while science can determine things like optimal color sensitivity (red) of a bass' eye, that doesn't necessarily indicate that the color red is therefore more attractive to bass, since attractiveness is determined only behaviorally, and behavior is largely an adaptation to (specific) environment. As such, it wouldn't be unexpected to see angler color experiences that seem to contradict each other (or the research), and it therefore shouldn't suggest that one example/person is right and so the other must be wrong. Then there are the areas of inconsistent opinion or (dis)agreement amongst even the researchers themselves on subjects like UV perception by bass.
Of course, this is all part of what makes bass fishing so interesting. 
Ultimately, each angler has to determine for himself how important (or not) any of this "color stuff" is to his own fishing.
-T9
J Francho reply :
I seem to recall that bass' eyes adjust quicker to lighting changes, faster than many prey items, hence their heightened activity during crepuscular periods (dawn and dusk).
SHaugh reply :
Another interesting idea is the refractive index as shown in the diagram:
http://astarmathsandphysics.com/o-level-physics-notes/o-level-physics-notes-a-fishs-view-of-the-world.html
In the fish eye view photo this is represented by the point where the blue sky ends and the band of bright green is present. This is the point where light reflects off the surface rather than traveling straight into the water.
This appears to be dependent on how deep the fish is as well. So the deeper the fish is the less direct sun spotlight area (blue sky) will be seen.
This could explain why it appears that fish are most affected by bright sun at the very narrow band of time when the sun is in that center blue area.
Bassun reply :
On 10/11/2014 at 12:22 AM, Team9nine said:The problem, of course, is that most of this color discussion (as has been already stated) is merely speculation. So while fun to discuss, it likely has little relevance to whether or not we each experience successful fishing, witness the differences in personal experiences shared on this forum topic.
-T9
I absolutely agree 100% with this. Mostly conjecture and supposition - but lots of fun discussion. And I hope my views are not taken as insulting to any opposing views, that certainly is not my intent. Just fun debate and discussion.
And wow, yeah there is a ton of debate in the field especially about UV sensitivity. In regards to that, I think the science is behind the tech and we are seeing lure manufacturers prove more in the UV arena than anyone!
Bassun reply :
On 10/11/2014 at 12:52 AM, SHaugh said:This could explain why it appears that fish are most affected by bright sun at the very narrow band of time when the sun is in that center blue area.
I think that's quite plausable. Considering that and how the lower angle of inclination of the sun would increase the traveled distance of light in water, thereby reducing its intensity - combined with the vertical field of view, it does make sense that they would be most impacted when the sun is high. Seems reasonable to me.
einscodek reply :
Like most hypothesis, there are experiences which dont quite fit as an all-pervasive explanation
such as seeing bass schools roaming only a few feet from shore in crystal clear water in less than a foot of depth in mid-afternoons and bright daylight
I too believe in the raptor effect.. but I wouldnt say that bass are always on the watchout for raptors under all conditions
WRB reply :
The hypothesis that raptors flying overhead affect bass location is BS!
The conversation regarding bright blue sky affecting bass location is also ordering on speculation, not fact.
Bass don't have the brain capacity to have fear, moving objects above the water can alarm bass as an instinctive warning and they react to warning.
The 1st Bassmaster Classic held on lake Mead, a extremely clear water lake at that time, was won by Murray using white spinner baits in shallow water with the sun overhead. Everyone else target cliff shaded areas believing the bass couldn't be in bright sun lite shallow water with no shad. When asked why he fished in clear shallow water with a spinnerbait he stated that is where I also fish! The wasn't any wind, maybe a slight breeze with temperatures over 110 degrees.
One of my best big bass spots is very close to a osprey nesting tree. I have to watch closely when casting trout swimbaits for those osprey, so they catch the lure in mid cast.
We have no idea how a bass brain processes the images their eyes captures and bass have big eyes for a good reason, to find prey.
Tom
SHaugh reply :
I have no doubt that at times there are overriding concerns for fish.. they simply follow whatever driving force compels them most at that moment.
I also have no doubt that most small creatures have a raptor effect to some degree. I have chickens in my yard. When I play with the dog sometimes I will throw the toy directly over the top of them. They invariably panic. Even when I do it repeatedly they will continue to react almost every time. I think this is what Tatertester experienced throwing a frog over resting fish.
I'm not sure a chicken is much smarter than a bass, but it would seem that the reaction is pretty much involuntary and not easily unlearned.
There is no doubt that fish are very aware and attuned to what is going on inside that small blue window directly over their heads.
Perhaps the occasional appearance of a blazing sun "god" within that little window might be all it takes for them to seek a place where he is no longer there ?
geo g reply :
On 10/11/2014 at 2:13 AM, WRB said:The hypothesis that raptors flying overhead affect bass location is BS!
The conversation regarding bright blue sky affecting bass location is also ordering on speculation, not fact.
Bass don't have the brain capacity to have fear, moving objects above the water can alarm bass as an instinctive warning and they react to warning.
The 1st Bassmaster Classic held on lake Mead, a extremely clear water lake at that time, was won by Murray using white spinner baits in shallow water with the sun overhead. Everyone else target cliff shaded areas believing the bass couldn't be in bright sun lite shallow water with no shad. When asked why he fished in clear shallow water with a spinnerbait he stated that is where I also fish! The wasn't any wind, maybe a slight breeze with temperatures over 110 degrees.
One of my best big bass spots is very close to a osprey nesting tree. I have to watch closely when casting trout swimbaits for those osprey, so they catch the lure in mid cast.
We have no idea how a bass brain processes the images their eyes captures and bass have big eyes for a good reason, to find prey.
Tom
One thing we have a lot of in Florida is Cypress trees in lakes, and lots of Osprey nests. I agree with your statement one of the best spots for big bass is very close to osprey nesting sites. The reason for this is, Ospreys and their chicks are messy eaters with lots of fish parts and dung in the water. Small fish flock to these areas for an easy meal. Big bass flock to the same area to feed on the bait fish and small bass. Where there is bait, big bass will follow.
We also have lots of pad fields, and thick weed growth in our lakes. If the shade is there, under bright conditions, bass will take advantage of the shade. If your fishing clear rocky lakes without pads and weeds they will not seek out what is not there!
WRB reply :
The osprey tree I am referring to is at least 100' away from water. It's the raptors shadow that a bass or other fish see. The problem with that theory is lots of non raptor birds fly over the water creating shadows all day long, the bass and other fish would be in a constant state panic.
Yes, when bass are young of the year living in cover they are prone to being a food source to birds, birds on the water like cormorants, grebes, herons. Gulls are the common airborne fish eating bird and bass often push smaller baitfish up to the surface where gulls take advantage of the baitfish along with the bass.
Dozens of gull shadows on the water doesn't panic the bass, they are conditioned to feed, not panic.
I present jigs to bass by making very long cast over 100', because the big bass are conditioned to be wary of boats. Deer or cattle walking along the shoreline or in the water doesn't seem to spook the bass, they have become conditioned to these events as not being a threat. If a 30' cast would produce strikes it would be a lot easier, that only works at night where I fish.
Tom
WRB reply :
Interesting sketch of a 2 dimensional world. How does this look from facing the bass with the eyes on the upper sides of it's head? Bass eyes don't rotate, the are fixed position and see very well except directly overhead or under head or from behind, those are considered blind spots.On 10/11/2014 at 12:52 AM, SHaugh said:Another interesting idea is the refractive index as shown in the diagram:
http://astarmathsandphysics.com/o-level-physics-notes/o-level-physics-notes-a-fishs-view-of-the-world.html
In the fish eye view photo this is represented by the point where the blue sky ends and the band of bright green is present. This is the point where light reflects off the surface rather than traveling straight into the water.
This appears to be dependent on how deep the fish is as well. So the deeper the fish is the less direct sun spotlight area (blue sky) will be seen.
This could explain why it appears that fish are most affected by bright sun at the very narrow band of time when the sun is in that center blue area.
Tom
Paul Roberts reply :
On 10/10/2014 at 11:43 PM, Bassun said:... as tatertester and Paul both conveyed the same in that casting directly over the fish has a negative impact in which they have personally noticed. ...
Think about why would fish respond so violently to something zipping overhead!
On 10/11/2014 at 12:22 AM, Team9nine said:The problem, of course, is that most of this color discussion (as has been already stated) is merely speculation. So while fun to discuss, it likely has little relevance to whether or not we each experience successful fishing, witness the differences in personal experiences shared on this forum topic. There is some stuff we do know, provided by detailed examination of the largemouth bass' eye from studies such as the 2002 Kawamura & Kishimoto paper which appears to be the most recent and heavily cited example in literature. From that study we know the following:
- The occurrence of C-response provides direct evidence for the possession of color vision. In this study, therefore, it is concluded that the largemouth bass can discriminate colors.
- The dominant L-response with a maximum at 673nm and three variations in C-responses might indicate a better color analysis at longer wavelengths, implying that the largemouth bass is able to discriminate red better than blue.
- In the largemouth bass, the visual axis is found in the nasal-temporal direction and the near point is 13.5 cm, indicating that sharp image formation is not performed when an object comes closer than 13.5cm from the eyes. This near point is slightly shorter than those of other teleosts.
- The retina of the largemouth bass is specialized to both movement and form perceptions.
Part of the problem is that while science can determine things like optimal color sensitivity (red) of a bass' eye, that doesn't necessarily indicate that the color red is therefore more attractive to bass, since attractiveness is determined only behaviorally, and behavior is largely an adaptation to (specific) environment. As such, it wouldn't be unexpected to see angler color experiences that seem to contradict each other (or the research), and it therefore shouldn't suggest that one example/person is right and so the other must be wrong. Then there are the areas of inconsistent opinion or (dis)agreement amongst even the researchers themselves on subjects like UV perception by bass.
Of course, this is all part of what makes bass fishing so interesting.
-T9
Well.. we know a bit more than that. We also know that cones are much less light sensitive than rods and are not even employed at very low light. Night adapted (scotopic) vision is entirely rod vision. Photopic and scotopic vision are entirely different. Rod vision is not color vision. Bass, like us, don’t see color at night, and probably little of it in low light. Although the bass' pupil cannot regulate light coming in, pigments do, their chief job being to protect those sensitive rods. Although bass haven’t been looked at specifically, in other fishes adaption to photopic vision occurs in less than half the time it takes for scotopic adaption -something like 20 minutes for fish studied. If you consider how long it takes for lighting to build starting at dawn, such a time period appears aptly quick.
As John mentions, bass appear to be adapted to crepuscular activity, and various studies have shown they have advantages over prey under reduced light.
Bottom line, pertaining to this thread is that bass appreciate reduced light levels. There is not one reason, or “cause”, for this. Like many things when dealing with evolutionary adaptations within complex environments, it’s a matter of multiple selective forces over a long period of time. There’s “wisdom” in there that is darn difficult to deconstruct.
Major selective forces for bass use of shade likely include:
- Lighting in the aquatic environment and all that affects it: Atmosphere, depth, surface conditions, water clarity.
- Visual capabilites of prey
- Visual signatures produced by prey
- The need for security from predators (including “raptor effect”) –real (immediate) or remembered (instinctual).
- Limitations such as competing needs (reproduction) and historical constraints (evol changes occur in steps, modifications rather than complete instantaneous overhauls), i.e. bass anatomy (including eye placement and functions) serve multiple roles from competing requirements. If bass had hooves, yes, they could see them all at once. Bass are doing the best they can in an immensely complex world. They certainly keep us predators on our toes.
Team9nine reply :
On 10/11/2014 at 7:19 AM, Paul Roberts said:
Well.. we know a bit more than that. We also know that cones are much less light sensitive than rods and are not even employed at very low light. Night adapted (scotopic) vision is entirely rod vision. Photopic and scotopic vision are entirely different. Rod vision is not color vision. Bass, like us, don’t see color at night, and probably little of it in low light. Although the bass' pupil cannot regulate light coming in, pigments do, their chief job being to protect those sensitive rods. Although bass haven’t been looked at specifically, in other fishes adaption to photopic vision occurs in less than half the time it takes for scotopic adaption -something like 20 minutes for fish studied. If you consider how long it takes for lighting to build starting at dawn, such a time period appear aptly quick.
LOL - that wasn't meant as an absolute statement/post of the only things we know about bass vision, Paul 
but it is one of the few published studies carried out directly on largemouth bass eyes and not inferred from the eyes/research of other similar fish. As such, it gets heavily cited. So while generalities certainly apply such as the rods and cones function you mention, one still needs to be careful about stating anything specific to a bass that hasn't been proven otherwise. A good example of this overgeneralization would be UV vision in juvenile sunfish members, where one published study found that juvenile pumpkinseed do use UV vision for some degree of feeding advantage, while another (different) study demonstrated that juvenile bluegill do not. So where would a juvenile bass fall, being in the same family? Schrodinger's Cat?
-T9
Paul Roberts reply :
On 10/11/2014 at 8:28 AM, Team9nine said:LOL - that wasn't meant as an absolute statement/post of the only things we know about bass vision, Paul
-T9
Very true, Brian. We should be careful assuming too much across taxa. But, I don't think it should be ignored -some things are older and shared across taxa. As an example, the red and green peak sensitivities measured in bass are similar (but not the same) to those measured in bluegill. Bass behavior (crepuscular activity, use of shade, prey capture rates) tends to conform pretty well to what's known about light regulation in fish eyes.
WRB reply :
Paul, you state flatly that bass can't see color at night based on eye elements of rods & cones.
Keith Jones agrees with the construction, I am not an expert on eye sight, however have spent more time on the water catching bass then most anglers, with the exception of Catt at night.
If night bass tournament anglers could win tournaments fishing all black or all white or a combination of contrasting black and white, they would. The problem is bass, at times, have a color preference at night that is the same or very close to the colors they prefer during day light.
I fish with my hair jigs often at night and use my basic black/purple/brown combination with black, purple or red-brown pork rind trailers. Some nights it's the purple or the red-brown or the black trailer, I never know what the bass prefer without trying all 3 color trailers. The bass definitely have a color combination preference at night and it's not always black! Strange since they can only see shades of gray at night....according to current science.
Tom
einscodek reply :
On 10/11/2014 at 2:13 AM, WRB said:The hypothesis that raptors flying overhead affect bass location is BS!
The conversation regarding bright blue sky affecting bass location is also ordering on speculation, not fact.
Bass don't have the brain capacity to have fear, moving objects above the water can alarm bass as an instinctive warning and they react to warning.
The 1st Bassmaster Classic held on lake Mead, a extremely clear water lake at that time, was won by Murray using white spinner baits in shallow water with the sun overhead. Everyone else target cliff shaded areas believing the bass couldn't be in bright sun lite shallow water with no shad. When asked why he fished in clear shallow water with a spinnerbait he stated that is where I also fish! The wasn't any wind, maybe a slight breeze with temperatures over 110 degrees.
One of my best big bass spots is very close to a osprey nesting tree. I have to watch closely when casting trout swimbaits for those osprey, so they catch the lure in mid cast.
We have no idea how a bass brain processes the images their eyes captures and bass have big eyes for a good reason, to find prey.
Tom
Id largely agree.. and they dont have much facility to rationalize like us
but I dunno that from instinct bass cant distinguish from built-in instinct types of overhead flight in the sky
if I were bass I'd be more afraid of the circling raptors (hawks, eagles)
I've seen other birds like cranes, pelicans, and herons who fly in a straighter pattern pick out bluegill but never any bass
I could envision hawks or eagles taking on larger fish such as bass and trout though
if a bass can pick me out on shore, I'd think they could pick out in clearwater flights of circling raptors overhead.
it'd be interesting to see if bass are sighted in shallow waters when birds of prey are circling above..
Paul Roberts reply :
On 10/11/2014 at 10:50 AM, WRB said:... I never know what the bass prefer without trying all 3 color trailers. ...
Why stop at 3? Odd, there aren't all that many colors available in pork. Contrast this with plastics which come in a huge variety of hues and combinations of hues. Interesting that color theories grow in complexity the more colors are offered. If you had the addition of say, olivaceous purple over motor oil with red flakes in a pork trailer, would it have been the answer that produced catches on a night when black, brown, and purple failed? On the night that the bass were only taking tequila-sunrise worms with a brown bloodline and burgundy #32 flakes in 60 fow, which color pork might they have preferred? And on the nights when the bass only took brown bloodline worms, no other contestants came in with good catches, unless they had brown bloodline worms?
If color is that critical, how much time does one spend testing all those colors that are offered? I mean, mix that in with time of day, prey activity, number of bass present, number of bass active, moon phases, sky and water conditions, and dumb luck, and... how could one expect to add bloodline color to the list of variables. I don't know about you but I've never been able to stop and replay time. Events and changes roll by me like a torrent. Bloodline hue or flake color just isn't in the running.
I find I choose my colors based on:
-what's offed by the manufacturers
-what makes me go "Ooooo!" in the store.
-and fishing results (in that torrent of events I mentioned above) which have lead me to believe that translucent worms work better in high vis conditions, and that opaques work better in lower vis conditions, and fluorescents may help in certain circumstances -turbidity, and high competition (between bass).
I think we humans are suckers for color, and poor at keeping track of, even recognizing, the variables inherent in astronomically complex environments.
WRB reply :
Paul, I make my pork trailers since Super Pork went out of business and they are white before dying. I use RIT liquid dye. The purple is not a grape color, it's looks very similar to the purple on original Stren mono boxes, more a violet purple. The brown is a mixture of dark brown and dark red I call barn red or brown-red, black is black. I also use white pork trailers on white/chartreuse/ dark green hair jig when the shad are spawning at night. For smallmouth bass prefer brown/chartreuse/red hair jigs with barn red trailer at night, rarely eat all black.
There isn't a limit of color combinations available for soft plastics...mind boggling possibilities,
We won a night tournament several years back using 1/8 oz dart head jigs with plain smoke 4 1/2" curl tail worms. My partner brought his spinning outfit with 6 lb line and caught all our keeper bass, I left my finesse rods at home. Lesson learned, you never know what bass may prefer, even at night.
Tom
Paul Roberts reply :
Mind boggling is something I try to avoid. I don't mean to come off... aggressively; it's my natural defensive response to being a thinker in a world that's.. just too big for thinking. It's frustrating to know I'll die barely scratching the surface of it all. "Color" is a topic that... I should probably avoid.
Bassun reply :
On 10/11/2014 at 10:50 AM, WRB said:Paul, you state flatly that bass can't see color at night based on eye elements of rods & cones.
Keith Jones agrees with the construction, I am not an expert on eye sight, however have spent more time on the water catching bass then most anglers, with the exception of Catt at night.
If night bass tournament anglers could win tournaments fishing all black or all white or a combination of contrasting black and white, they would. The problem is bass, at times, have a color preference at night that is the same or very close to the colors they prefer during day light.
I fish with my hair jigs often at night and use my basic black/purple/brown combination with black, purple or red-brown pork rind trailers. Some nights it's the purple or the red-brown or the black trailer, I never know what the bass prefer without trying all 3 color trailers. The bass definitely have a color combination preference at night and it's not always black! Strange since they can only see shades of gray at night....according to current science.
Tom
I would contest again that you may not be seeing a result from the fish necessarily "seeing" the specific color, however, we do know that rods are most effective with certain wavelengths of reflected light. I think it stands to reason, that what could be happening is you are stumbling into the correct wavelength in which the rods are most capable of registering the light reflected. You could simply be stumbling into the best case scenario to build contrast and make the lure more easily seen by a bass. The difference in color choice could be influenced by any number of variables in the water.
Beyond that, I think it's also plausible that certain shades of grey could be the actual trigger. If bass cannot see full spectrum at night - it would stand to reason they would learn to focus on certain shades of grey and target that. Conversely, they may be able to utilize a mix of rods and cones even in ultra low light and be able to differentiate certain colors. I think as the depth increases, we would have to agree the amount of reflected light is going to drop - so there will eventually be a point where color, of any hue, just simply wont matter. New moon, turbid water, 50 feet deep, on a wilderness lake -- there just isn't too much light to begin with...
All kinds of possibilities!
WRB reply :
Way back in the early 60's the Lew Eppinger, company maker of Dare Devil spoons, changed their paint supplier and afterwards the sales of their most popular red/white spoon dropped way off on all sizes. The customer complained the old red/white spoons catch fish, the new spoons are not nearly as good. Eppinger didn't change the tooling only the red paint supplier. The red color looked exactly the same shade as the original color. They went back to the original paint supplier and the sales picked back up.
Eppinger sent the red paints for analysis to determine what the difference was. Under ultra violet light the 2 reds were very different, the original looked bright and nearly glowed, the new red was almost dull gray.
This leads me to think that fish see colors very differently than the human eye and explains how bass see some colors well in the dark.
Tom
PS, source Jason Lucas.
Bassun reply :
On 10/12/2014 at 10:41 AM, WRB said:Way back in the early 60's the Lew Eppinger, company maker of Dare Devil spoons, changed their paint supplier and afterwards the sales of their most popular red/white spoon dropped way off on all sizes. The customer complained the old red/white spoons catch fish, the new spoons are not nearly as good. Eppinger didn't change the tooling only the red paint supplier. The red color looked exactly the same shade as the original color. They went back to the original paint supplier and the sales picked back up.
Eppinger sent the red paints for analysis to determine what the difference was. Under ultra violet light the 2 reds were very different, the original looked bright and nearly glowed, the new red was almost dull gray.
This leads me to think that fish see colors very differently than the human eye and explains how bass see some colors well in the dark.
Tom
PS, source Jason Lucas.
UV is certainly a possibility. We've all seen tests which show UV coated paints preform better than no UV offerings --- and tests which show no difference, lol. I think, on a personal level, that there is merit to UV being in the fishes spectrum, whether as a "see-able" color or merely a brighter reception of light by the rods - who knows. Either way I would love to see more research to verify what really is going on. 
RB 77 reply :
This is a very interesting discussion. The one thing that I can add is that in my experience color definitely does matter. Some times it doesn’t and they will bite anything in the box. Other times it is of the utmost importance. Most people that have fished at any length of time and have paid attention have come across a pattern where color has played an important part of that pattern.
I have developed patterns fishing a soft plastic where color was so critical that the same exact presentation with a variety of different color plastics yield no results unless using that one same color. One instance the particular color was Junebug. Black, Watermelon, Greenpumpkin, etc yielded no results. Even Grapeseed, in which I use the same colorant as Junebug, was not as successful. The color of the flake (green vs. black) was even critical.
SHaugh reply :
I think it makes perfect sense that a creature evolving in a murky underwater world will be constantly developing ways to see better in that world. Developing an ability to better distinguish things in darkness or low light conditions would be an obvious evolutionary driver.
Fish spend most of their days in low light to total darkness. Because of the reflective powers of water the amount of sunlight that can penetrate their environment is significantly less than the air environment.
It also stands to reason that eyes and brains that have evolved and are predisposed to vision in those conditions will be less tolerant of conditions that are significantly brighter. Like when direct sunlight is in that small blue window overhead. That by far explains a fishes desire for shade during those times much better than raptors or hunting advantages imo.
UV and infrared vision is probably something fish scientist should spend more time on. I've had some experience with night vision gear. Isn't it also possible that fish eyes have some ability to see the infrared spectrum ? The concepts of emissivity and background emissivity probably goes a long way toward explaining different color performance. Some color / material combinations probably register as much warmer or cooler than the background, thereby enhancing their visibility in lower light conditions.
Here's an interesting article that explains emissivity pretty well.
http://x26.com/irpaper_emissivity.htm
It seems to me that in a lower light environment infrared would be the chosen evolutionary path rather than UV. It might not have the range of UV underwater, but in the up close personal world of a fish it could be very useful.
I found a good read for science types.... I'm going fishing....
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0064429
WRB reply :
Exactly, we don't know how bass or other game fish "see" colors based on rods and cones independently from their environment. Most of the living prey that predators feed on must be able to find each other and hide from predators, the predators must evolve to find the prey. If bass could only see details in good light conditions, they wouldn't survive.
If we think bass anglers are into lure colors, try competitive marlin and tuna anglers with nearly unlimited funds to research those fish. There are some good research on fish eyesight by Australians for marlin that may be of interest.
When experience flies in the face of science, trust your instincts, there is more to how fish see colors than we currently know.
Living critters that bass feed on are not solid colors and have a living sheen of multiple complex coloration. Lure manufacturers try to duplicate a living color scheme to the human eye to sell their products, we try to get bass to eat those lures.....sometimes it works!
Tom
Bassun reply :
On 10/13/2014 at 9:26 PM, SHaugh said:I think it makes perfect sense that a creature evolving in a murky underwater world will be constantly developing ways to see better in that world. Developing an ability to better distinguish things in darkness or low light conditions would be an obvious evolutionary driver.
Fish spend most of their days in low light to total darkness. Because of the reflective powers of water the amount of sunlight that can penetrate their environment is significantly less than the air environment.
It also stands to reason that eyes and brains that have evolved and are predisposed to vision in those conditions will be less tolerant of conditions that are significantly brighter. Like when direct sunlight is in that small blue window overhead. That by far explains a fishes desire for shade during those times much better than raptors or hunting advantages imo.
UV and infrared vision is probably something fish scientist should spend more time on. I've had some experience with night vision gear. Isn't it also possible that fish eyes have some ability to see the infrared spectrum ? The concepts of emissivity and background emissivity probably goes a long way toward explaining different color performance. Some color / material combinations probably register as much warmer or cooler than the background, thereby enhancing their visibility in lower light conditions.
Here's an interesting article that explains emissivity pretty well.
http://x26.com/irpaper_emissivity.htm
It seems to me that in a lower light environment infrared would be the chosen evolutionary path rather than UV. It might not have the range of UV underwater, but in the up close personal world of a fish it could be very useful.
I found a good read for science types.... I'm going fishing....
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0064429
That second article definitely opens the thought to IR / NIR light ranges being important for sure!
Driftb reply :
Should the question be what do the bass see? Maybe we should be asking what the prey see. I fish a medium sized clear water river. It isn't uncommon for the bass and trout to bite better when the sun goes behind a cloud than in full sun. The bass are taking advantage of the fact that it is hard to see from a sunny area into a shaded area. Fur.thurmore, baitfish's eyes will be adaptedto sunshine so when they swim into the shade they will be blind until their eyes adjust.
As for the raptor effect? I notice that the larger fish are less likely to be found near the surface on sunny days. In the Delaware, any fish that isn't deep or near cover won't get much bigger. We see eagles catch fish every day.
Bassun reply :
Regardless of all conjecture, and suppositions, I'm really pleased with how interesting this topic became. Thanks to everyone who has replied... you've made this quite interesting.
Team9nine reply :
I'd disagree on the IR/NIR being that important in the overall picture, especially after reading that paper. Keep in mind that bass have been around for over 2.5 million years. There isn't going to be any sudden evolutionary change that makes them start using IR/NIR just because they find themselves in your murky reservoir. As the paper stated, even in pure water, only the very shortest of the IR wavelengths have the ability to penetrate more than 5 or 6 feet in the water column. In any type of murky water/eutrophic environment with some degree of DOM (dissolved organic matter), which is most waters, you're talking at best, penetration of just inches or less. The fish that they studied that showed the greatest ability to detect IR/NIR evolved in the shallow murky backwaters of the Nile/Mozambique R. The other mentioned species which displayed some degree of IR/NIR capabilities, while living in clearer water environs, were surface feeders that spend much of their life in the top couple inches of the water column. Neither of these cases is applicable to largemouth bass, in general. That said, just like UV, I certainly wouldn't be surprised to see some enterprising lure company promote some type of IR/NIR paint scheme on their lures in the future as "the next big thing" - and some pro will promote it as sliced bread, and people will buy it
-T9
Bassun reply :
On 10/14/2014 at 10:17 PM, Team9nine said:I'd disagree on the IR/NIR being that important in the overall picture, especially after reading that paper. Keep in mind that bass have been around for over 2.5 million years. There isn't going to be any sudden evolutionary change that makes them start using IR/NIR just because they find themselves in your murky reservoir. As the paper stated, even in pure water, only the very shortest of the IR wavelengths have the ability to penetrate more than 5 or 6 feet in the water column. In any type of murky water/eutrophic environment with some degree of DOM (dissolved organic matter), which is most waters, you're talking at best, penetration of just inches or less. The fish that they studied that showed the greatest ability to detect IR/NIR evolved in the shallow murky backwaters of the Amazon. The other mentioned species which displayed some degree of IR/NIR capabilities, while living in clearer water environs, were surface feeders that spend much of their life in the top couple inches of the water column. Neither of these cases is applicable to largemouth bass, in general. That said, just like UV, I certainly wouldn't be surprised to see some enterprising lure company promote some type of IR/NIR paint scheme on their lures in the future as "the next big thing" - and some pro will promote it as sliced bread, and people will buy it
-T9
Even if it is only visible in a very short distance, the right IR/NIR effects could make the difference between a fish turning away at the last second vs taking the bait. I agree the transmission isn't going to pull fish from 20 feet away, but if it helps get the hit vs just being "checked out" then it may have a place in the discussion. Maybe it doesn't impact anything, but given what little we know, it seems at least plausable that it could enhance a lure.
J Francho reply :
Location and presentation are much, much more important than anything else in this thread. Two things even seasoned measurebaters get wrong. 
If you're worried about IR/NIR, and how it might effect your tournament results, you already lost. If you're that good that you can fine tune this, then I humbly bow.
That's not to say this isn't interesting stuff, but whenever the discussion turns towards using the info as an advantage, I start smelling bad science, and marketing hype.
That's just my opinion.
Team9nine reply :
On 10/14/2014 at 10:53 PM, Bassun said:Even if it is only visible in a very short distance, the right IR/NIR effects could make the difference between a fish turning away at the last second vs taking the bait. I agree the transmission isn't going to pull fish from 20 feet away, but if it helps get the hit vs just being "checked out" then it may have a place in the discussion. Maybe it doesn't impact anything, but given what little we know, it seems at least plausable that it could enhance a lure.
Don't confuse short eyesight distance with distance that IR light penetrates underwater. The only real possibility might be during a surface strike. For any lure fished at any normal depth, especially anything over a foot or two deep in most waters, the IR rays would never penetrate deep enough into the water to make IR vision a reality. Thought of another way, if you've ever night fished with a black light and fluorescent blue line, that line isn't glowing all the way down to your lure fished in 20 feet of stained water. That line would appear to "glow" only as deep as the UV light can penetrate into the water before becoming attenuated. Beyond that, it would look like plain old blue/clear line. Additionally, even assuming bass had any sense of IR perception, why would we automatically correlate it to feeding and lures (beside the fact we're bass anglers) and not some other more biologically important phenomena. With IR being a "heat" signature, it would seem largely counterproductive in a cold blooded world except in very specialized adaptations.
-T9
WRB reply :
This thread is title the raptor effect or why bass are found under cover, the assumption being predator birds created this behavior. The topics of how bass see underwater in low light followed is logical, bass under cover are in a low light location and are primarily sight feeders.
Bass behavior dictates their location, understanding bass behavior helps to determine location. How to catch the bass you find is more about presenting a lure that the bass will strike. To ignore the possibility that bass can see color in poor light eliminates a wide range of lures and colors to present to the bass.
Tom
webertime reply :
I'm going to tip toe into this. AKA random thoughts and what I could remember due to my ADD.
I think we can all agree that Bass populations in different bodies of water can act very differently. Heck even the same body of water can have several population groups of Bass that behave in different manors... How they react to bait color, or overhead cover, or how they feed can vary from one population to another.
Regarding the raptor effect. I believe in it 100% for fish that must live in shallow areas. My brother is a trout guide on the South Island of New Zealand. The water is clearer than you can imagine. Time and time again he's had clients show up and be in the wrong colored shirt of just make movements that are too fast and watched a "Supertanker" (8+lb trout) turn slightly to them, then swim off. This is at distances of 50+ feet, with various backgrounds behind them. A trout (or a Bass) living in shallow and clearish water will be more wary of predators above them as they don't often have hiding spots instantly available.
I think bass must be able see in colors and it important to an extent. To me I have found that colors and how they create a profile in water of a given clarity is hugely important. For example I have found that a the swimbait with a darker top catches more in darker/stained water. In clear water it didn't make much of a difference what color I threw. Or when I fish a plastic craw with the tips dyed (or a lighter bottom laminent), I catch 10:1 over solid colors up here when fishing for smallies, regardless of water clarity. I have found the color itself didn't matter as much as having contrast on the bait. Maybe the blue vien that WRB mentioned in that night tournament was the same sort of thing?
As Francho, pointed out if you (or I) get caught up on this level of minutia when fishing we aren't going to succeed.
Occam's Razor.
J Francho reply :
Great post, weber.
SHaugh reply :
On 10/15/2014 at 12:13 AM, Team9nine said:Don't confuse short eyesight distance with distance that IR light penetrates underwater. The only real possibility might be during a surface strike. For any lure fished at any normal depth, especially anything over a foot or two deep in most waters, the IR rays would never penetrate deep enough into the water to make IR vision a reality. Thought of another way, if you've ever night fished with a black light and fluorescent blue line, that line isn't glowing all the way down to your lure fished in 20 feet of stained water. That line would appear to "glow" only as deep as the UV light can penetrate into the water before becoming attenuated. Beyond that, it would look like plain old blue/clear line. Additionally, even assuming bass had any sense of IR perception, why would we automatically correlate it to feeding and lures (beside the fact we're bass anglers) and not some other more biologically important phenomena. With IR being a "heat" signature, it would seem largely counterproductive in a cold blooded world except in very specialized adaptations.
-T9
I'm no scientist.. and I agree that if we are worrying about this level of minute detail we are probably not going to catch very many...
But what I am not understanding about your comments is the idea that thermal radiation must originate or be reflected sunlight originating outside the water environment. Don't cold blooded animals still generate internal heat ?
isn't thermal radiation created within materials and organisms ? If water at night becomes a near perfect blackbody, wouldn't even the slightest thermal radiation created by a prey fish's digestion or muscle contractions create a slight difference in the comparative emissivity against the blackbody background... at least for a few feet around the source ?
Or perhaps a 70 degree worm being thrown into 60 degree water register as warmer than the surrounding water at least for a few seconds ? Has anybody ever tried fishing with warmed plastic baits ?
Couldn't the ability to see those slight differences in emissivity be a significant advantage and driver ?
I don't think water is as uniform a temperature as we are inclined to believe. For example if a crappie fry has spent most of the day in warm shallow water and then moves to colder deep water how long will it take before it's body temperature adjusts to the ambient level ? During that time wouldn't it be possible to see it's infrared signature as being different than the background ?
Team9nine reply :
On 10/15/2014 at 2:47 AM, SHaugh said:
On 10/15/2014 at 12:13 AM, Team9nine said:Don't confuse short eyesight distance with distance that IR light penetrates underwater. The only real possibility might be during a surface strike. For any lure fished at any normal depth, especially anything over a foot or two deep in most waters, the IR rays would never penetrate deep enough into the water to make IR vision a reality. Thought of another way, if you've ever night fished with a black light and fluorescent blue line, that line isn't glowing all the way down to your lure fished in 20 feet of stained water. That line would appear to "glow" only as deep as the UV light can penetrate into the water before becoming attenuated. Beyond that, it would look like plain old blue/clear line. Additionally, even assuming bass had any sense of IR perception, why would we automatically correlate it to feeding and lures (beside the fact we're bass anglers) and not some other more biologically important phenomena. With IR being a "heat" signature, it would seem largely counterproductive in a cold blooded world except in very specialized adaptations.
-T9
I'm no scientist.. and I agree that if we are worrying about this level of minute detail we are probably not going to catch very many...
But what I am not understanding about your comments is the idea that thermal radiation must originate or be reflected sunlight originating outside the water environment. Don't cold blooded animals still generate internal heat ?
isn't thermal radiation created within materials and organisms ? If water at night becomes a near perfect blackbody, wouldn't even the slightest thermal radiation created by a prey fish's digestion or muscle contractions create a slight difference in the comparative emissivity against the blackbody background... at least for a few feet around the source ?
Or perhaps a 70 degree worm being thrown into 60 degree water register as warmer than the surrounding water at least for a few seconds ? Has anybody ever tried fishing with warmed plastic baits ?
Couldn't the ability to see those slight differences in emissivity be a significant advantage and driver ?
I guess I would argue several points. First, since bass evolved over 2 million years ago, there would have to have been some evolutionary need or benefit to them adopting IR vision abilities back then. To that point, I've yet to see any research that supports IR vision in bass. Not saying they don't, just that it's pure speculation at this point.
Next, even if they were proven to see IR, you'd still have to have a reason (advantage) for that development, and the automatic assumption that it would have to do with feeding is tenuous at best. Perhaps it would be for mate or nesting area selection, or predator avoidance, or a whole host of other reasons. Again, as anglers, we like to grasp onto things that potentially fit our idealizations, but that may not be the case, even if it seems plausible.
As for cold-blooded animals, the IR and thermal images I've seen taken of them show no signs of having "hot spots" or "auras" or other such differences that would stand out, at least not on thermal imaging cameras. They take on the temperature of their environment, and tend to blend in to their background environment instead of stand out (from an IR imaging perspective). Again, they can "hold" some outside heat relative to a background temperature to give them a signature short term, but it seems highly unlikely bass would have evolved to develop IR vision simply on the chance that some warmer than water creature would fall into the lake so it could eat it before taking on the local water temperature and blending in again, or making it back to land/air safely...and the idea of heating a plastic worm up between casts so it would have an IR signature just seems like a far overreach. That said, anyone who wants to take the time to test this out, please report on your findings.
Instead, and taking this in a totally different direction, what you propose about muscle contractions, digestion, etc. would, to me, fall more under the category of electroreception - think sharks and rays, some catfish, paddlefish, etc.. As I understand it, all living creatures give off small electrical impulses due to muscular movement. But again, from the researchers I've seen go on record on this subject, the consensus has been that bass don't have this ability...but it gives us another wonderful area to talk about now
-T9
Bassun reply :
On 10/15/2014 at 1:19 AM, webertime said:My brother is a trout guide on the South Island of New Zealand. The water is clearer than you can imagine. Time and time again he's had clients show up and be in the wrong colored shirt of just make movements that are too fast and watched a "Supertanker" (8+lb trout) turn slightly to them, then swim off. This is at distances of 50+ feet, with various backgrounds behind them. A trout (or a Bass) living in shallow and clearish water will be more wary of predators above them as they don't often have hiding spots instantly available.
I absolutely agree that scenario would certainly put the fish on high alert for non-waterborn predation. I remember reading an article a long time ago about a man who would stalk smallmouth bass. He would literally wear camo, and crawl around keeping his body and profile hidden or at least below (I want to say) a 20 degree inclined line of site. Then he would attempt to make one single cast with a live crayfish.
That's the extreme, but certainly not lost on your brother.
On 10/15/2014 at 12:13 AM, Team9nine said:Don't confuse short eyesight distance with distance that IR light penetrates underwater. The only real possibility might be during a surface strike. For any lure fished at any normal depth, especially anything over a foot or two deep in most waters, the IR rays would never penetrate deep enough into the water to make IR vision a reality. Thought of another way, if you've ever night fished with a black light and fluorescent blue line, that line isn't glowing all the way down to your lure fished in 20 feet of stained water. That line would appear to "glow" only as deep as the UV light can penetrate into the water before becoming attenuated. Beyond that, it would look like plain old blue/clear line. Additionally, even assuming bass had any sense of IR perception, why would we automatically correlate it to feeding and lures (beside the fact we're bass anglers) and not some other more biologically important phenomena. With IR being a "heat" signature, it would seem largely counterproductive in a cold blooded world except in very specialized adaptations.
-T9
I wasn't referring to short sighted bass, I was actually referring to the short distance IR wavelengths would be able to travel in water. Your example of UV light becoming attenuated in water is a great visual, though, for how light acts in water.
On 10/14/2014 at 11:30 PM, J Francho said:Location and presentation are much, much more important than anything else in this thread. Two things even seasoned measurebaters get wrong.
If you're worried about IR/NIR, and how it might effect your tournament results, you already lost. If you're that good that you can fine tune this, then I humbly bow.
That's not to say this isn't interesting stuff, but whenever the discussion turns towards using the info as an advantage, I start smelling bad science, and marketing hype.
That's just my opinion.
Oh, I don't think anyone here is thinking they are going to make the next best things because we suddenly decided IR/UV/X-Rays are visible to fish. I think were mostly talking in conjecture filling the gaps of science with our own theories and assumptions. I can almost guarentee you that there is some bad science here, lol. But, as long as we all take it as such and maybe even learn somethign along the way, then yay
Course those Livingston lures were called hokum by many until Howell won the classic with one... I've not used one yet, but the idea of adding additional light and sound does seem like a potentially good idea... If I can just get over the idea of fishing with an electronic fising lure...
J Francho reply :
A couple of things, bass (boney fish) are poikilotherms, meaning they operate at a large range of body temperatures, compared to ectotherms (think turtles or lizards) that must warm and cool their bodies in order to forage, digest, and reproduce.
I saw a quick quip about evolution and advantage - this is a misnomer. Just because a trait is inhereted, it doesn't mean it has to serve a purpose. It just means it's not a disadvantage that natural selection has weeded out.
Sorry, I'm not much help here, carry on.....
Bassun reply :
I just thought about the entirety of this thread and found it funny how it has transmogrified from a serious article highlighting the "Raptor Effect" and now we've take it to the point of heating our worms, lol.
Team9nine reply :
On 10/15/2014 at 3:58 AM, Bassun said:I wasn't referring to short sighted bass, I was actually referring to the short distance IR wavelengths would be able to travel in water. Your example of UV light becoming attenuated in water is a great visual, though, for how light acts in water.
Perhaps I misunderstood, but I took your short distance to mean, say, bass within inches of prey, even at depths. My point was that this could only happen in very shallow water (<2') where you would have an IR signal to detect in the first place due to proper wavelength penetration, and that it wouldn't be able to happen at any depth beyond that, IMO. And yes, I'm taking this all as "interesting discussion" and nothing much more serious than that. Perhaps one day we'll actually get answers
-T9
SHaugh reply :
I think cold blooded animals can still have a temperature variation from air or water. While not significant it will still be there. Especially against water which becomes an almost perfect blackbody.
Note the snake and the mouse...
I would not dismiss the idea that an animals eye could evolve to be much more sensitive than our current camera technology as well. While not generating the intense hot spot that a warm blooded animal does, it could still be a very discernible difference.
SHaugh reply :
On 10/15/2014 at 4:09 AM, Bassun said:I just thought about the entirety of this thread and found it funny how it has transmogrified from a serious article highlighting the "Raptor Effect" and now we've take it to the point of heating our worms, lol.
You could keep them in your mouth.... maybe that's the real reason it works ice fishing....
If I was a serious night tournament guy I would think about trying it... depending on the lures mass it would take many seconds for a warm lure to become water temperature... in that time it might generate enough contrast to look very tasty.....
Team9nine reply :
Ahh, a fish out of water...err, a snake in the air (the journal Cell), is not the same as a fish underwater. Show me an underwater IR image of a fish or some other critter under natural lighting (or at night, unaided) and I'll be much more interested in your theory. I've never seen one. The very few underwater IR pictures I have seen all required accessory IR lighting at very close distances (e.g., 200 IR LEDs at <20" at night, 50 IR LEDs during the day) to make a discernible image. Yes, a basses eye could have evolved to be able to see what technology doesn't currently allow, but for now, I'm still hedging my bet on the more reasonable solution...but please don't let my skepticism stop anyone from creating an IR bass lure and making millions
-T9
SHaugh reply :
It would actually be pretty easy... and you wouldn't even need your mouth...
just put a coffee can of water over a small camp stove simmering next to you .... dip your lure for a second and pitch...
Bassun reply :
Right now there is someone somewhere reading this thinking.... hmmm... that's not a bad idea. I might just try that...
Howie90deg reply :
I hope you enjoyed my discussion of "the Raptor Effect.” Clearly there are a thousand reasons why a bass will act a particular way, drop to a specific depth or move to certain location. My hope was to have my fellow anglers consider a rarely discussed facet of our fishing experience, the birds of prey. Have a great day and remember to set the hook.
Grizzn N Bassin reply :
I enjoyed reading this great posts guys!
bassr95 reply :
I don't know about all that, but I sure catch a lot of bass under docks! 
Paul Roberts reply :
On 12/12/2014 at 8:25 AM, Howie90deg said:I hope you enjoyed my discussion of "the Raptor Effect.” Clearly there are a thousand reasons why a bass will act a particular way, drop to a specific depth or move to certain location. My hope was to have my fellow anglers consider a rarely discussed facet of our fishing experience, the birds of prey. Have a great day and remember to set the hook.
Thanks, Howard. I enjoyed the article. In the small reservoirs I fish along the CO front range, predatory birds are almost constant threats to fish. We have kingfishers, terns, various herons (both day and night), grebes, mergansers, osprey, bald eagles, and pelicans. We have several nesting pairs of osprey that scan my waters daily. I've watched bald eagles nabbing fish (usually carp -esp the bright orange fish-bowl releases ). A ring of pelicans can be almost frightening to watch in their efficiency -especially during drought years. And watching grebes hunting in clear water under bright skies has given me a respect for endothermy that I couldn't have realized prior. They are fast and relentless!
Again, thanks for being a catalyst for an interesting discussion.
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