Fishing Line Visibility

[jurelometer]

Regarding visibility, I am skeptical (along with Nelz and others).

Actually, I'm firmly convinced that fluoro works as claimed because I catch more fish when I use it, and consistently out-catch those around me not using it.

The truth is if you stick your head underwater with a dive mask, both nylon and fluoro are very visible to the human eye.

Have you tried this yourself?

Yes.  Took video  too.  I'll see if I can dig it up.   But you can also verify for  your situation when you see the  leader when you are winding it in in the waters that you fish.  Tie a section of nylon to a section of fluoro.   One other thing that I just thought of is to see if there is a difference in the shadow cast by the leader on the bottom in shallow water. I know that the shadow of a fly line freaks outs some shallow water species.

Sorry for assuming that you were one of us skeptics.

I'm guessing water clarity has a lot to do with grey scale. Here in the NW we have green water that maybe has 10' of "naked eye" visibility. Blue water would allow more sunlight to deeper water, thus altering the grey scale, but at some point everything loses it's color and is seen as a shade of grey. Some colors disappear at shallower depth than other colors  Red is the first color to blend in with gray scale. It supposedly happens around 30-40' in our brackish green water. Fish have a broader spectrum of ultra violet light that goes well beyond where it turns pitch black to the human eye. There is lot of discussions about the subject on the www

.....edit: it's a deep subject  

-Ted

It does get  sorta complicated.

[Another science fanboy warning- I have been reading papers on this stuff. I am not a trained expertI.  If somebody out there is actually formally educated in this stuff, feel free to correct]

FWIIW,  Some of the stuff that  I see in the fishing publications about light, water and fish vision does not line up with the scientific literature.  From what I have read on the science side:

Water clarity is determined by the solid objects mixed in with  it (particulates, algae, etc.).   Pure water will allow a limited range of  electromagnetic  wave frequencies from the sun to to partially pass through.  What we call visible light are these water compatible frequencies.  Sort of makes sense, since our eyes are filled with mostly water.

 An object appears to be blue because its surface contains just the right type of atoms that reflect light waves of blue frequency.  No blue light wave, no blue color.  White objects are reflecting the full range of visible  light waves.  An object that is not reflecting any available light waves will appear as black (the absence of light).

Blue light has a higher frequency (more waves per second) than green light, so it carries  more energy at a given amplitude.  This means it usually has to pass through more water to get all that energy absorbed.   Usually...

When light waves hit the water, some are reflected back at the surface, some are reflected back from water at various depths.   Green water is green because it is less clear/pure, containing substances (algae?) that absorb blue light. There is not as much blue light left to reflect back.  This also means that blue light waves will not make it as deep as  green  light waves will in  green water.   This is why fish that live in inshore green waters have only/mostly  cones (a type of light receptor in the eye) that respond only to green light waves. These fish have little or no ability to see blues and reds.  Conversely,  open ocean blue water species often have mostly/ only blue cones and few/no cones for green and reds.  There are exceptions, including species that spend enough time near the surface or in the shallows.

That 30 foot depth for red light waves  is only for perfect conditions at the equator in very clear water.  As light hits the water at greater angles and as particulates in the water increase, depth penetration of light waves decrease.   Also the amount  and intensity of light waves will be steadily decreasing with depth,  meaning that even in perfect conditions, nearly all  of that red light is gone at 30 feet (a red object is going to appear  gray with a slight red tint).

Most fish species that we target in saltwater do not have the  ability to see UV light.  This is because a)  UV light is at the borderline of frequencies that can pass through water, so it needs perfect conditions to penetrate (no reason to waste eye real estate  on UV receptors that won't be used )  and b) UV light is damaging to cells, so species that could be exposed to UV light frequently have a pigment in the eye (fluid?) to filter out UV.  In the Pacific NW green inshore waters, UV light probably only makes it down a couple feet..

But UV vision does play a role more frequently with shallow clear water species.  

As light  waves of the various frequencies are being filtered out, objects with pigments that would reflect these colors  appear grayer and eventually black, assuming that the eye had the ability to see that color in the first place, otherwise just grey to black (see the following on rod cells).

In addition to cone cells, the eyes also have rod cells that are much more sensitive, and fire off over a wider range of light frequencies (colors) somewhere  within  the green through violet range.  The more compromised the visual environment, the greater the total number of rods and the ratio of rods to cones.  These fish are more likely to see something than a human at depth, but the tradeoff is in visual acuity.  Fish species  that have cones for only one color are  using the cones for sharpening the image when there is enough light, as opposed to trichromatic creatures  with big brains (like  humans) that are using three different types cones spread out in a wider matrix to obtain a richer and more complex image.  

But getting back on topic:

With some exceptions, most of the species that we tend to target in saltwater don't see much in a range of colors, and don't have much in the way of visual acuity, but excel at making out profiles at distance when working with limited visibility.  So a bit of difference in visibility of a nearly invisible thin straight line attached to some potential food is not such a big deal IMHO.

Or something like that...  . I am sure a proper physicist or  marine biologist  would cringe a bit at these descriptions, but hopefully I have captured the gist of it.

-J

[thorhammer]

Red igloo coolers counteract whatever impact any other coloration may have. The pruf is in the butting. 

[nelz]

I know I can see the fluoro when I'm reeling in a lure, just assumed it got less visible when deeper. But whatever the reason, like I said, it seems to work, as in, I catch more fish with it when in clear water conditions.

[gstours]

Thanks Dave for your explanation,   Now I have to throw out my superstitious lucky 🍀 lure and get reel.🎣
   I've already changed some of my thinking for the new year.
Butt the. Red cooler stays 🤦‍♀️

[Brewcrafter]

And to further obfuscate the discussion:  Jurelometer was important to specify saltwater, I'm sure that light reacts totally differently with a different refractive index in fresh water.  I do remember many nights on lakes in SW Missouri fishing for largemouth, where the de-rigueur routine for bass fishing the shallows at night was a black light mounted on the side of the boat (UV-A) and brightly colored yellow line that would literally glow in the light.  The process being that as you were working a lure (usually a dark colored plastic) the key indicator was not what you felt, but to see the line "tick" when gently picked up by a largemouth (very few smashing hits in this type of fishing) and as it slowly moved to set the hook.  totally different set of circumstances but all relevant to "how fish see vs. how we see".  Thanks for all the good discussion. - john

[jurelometer]

 Ooh, good point.  When you reflood the garage, better to use saltwater. 


-J

[Makule]

We only fish in saltwater here.  Fluoro is more effective in getting the bite than regular mono, all other things being equal.  It's easily demonstrated in side by side comparisons:  Two guys fishing next to each other using same outfits, baits, hooks, and the exception being fluoro vs regular.  The fluoro will get the strikes and the regular will not, consistently.  Guess who was using the regular mono and got skunked.  I even used much smaller line (60 regular vs 150 fluoro) and didn't get any strikes while the guy next to me got 4 strikes within the hour.
Thinking this experience was just a fluke, I've using regular mono and have just not been getting any strikes.  I've switched back to fluoro but haven't had enough fishing time with it (only used it once recently for one set).
Where I usually go has a lot of fishing pressure so I suspect that has a lot to do with line visibility and bite.  I need to keep better track of where the use of fluoro makes a difference and where it does not.