Sunday, October 26, 2014

Simplifying the Great Debate: Fluorocarbon vs. Nylon: INVISIBILITY

I read and hear conversations all of the time debating the advantages & disadvantages of nylon monofilament vs fluorocarbon monofilament for leaders and tippet.  Once again, the real question is:  How much of the stuff you hear/read on this topic is truth versus marketing hype?  Let’s see if we can sort some of this out.


TRUTH:  Fluorocarbon has a closer refractive index to water than that of nylon.

Yes folks this is a cold hard scientific fact.  Refractive index essentially refers to a number indicating  how much the speed of light is reduced in a given medium.  I just got a headache from typing that.  Water has a refractive index of 1.3330.  Fluorocarbon has a refractive index of 1.42.  Nylon monofilament refractive indices range from 1.53-1.62.  BUT, does that really mean fluorocarbon is invisible in water?

MYTH: Fluorocarbon is nearly invisible to fish in water.

Clear back in 2001 a guy named Jeff Thomson wrote an article called, “Mathematical Theory of Fishing Line Visibility”.  Now, I can’t find that this is an actual peer reviewed published article, but I have read the presentation he did on the topic and it is pretty good.  He essentially breaks down how light refraction, reflection, and scatter in water works from a mathematical equation perspective and then applies the properties of water and fluorocarbon in those equations.  It’s painful to read if you do not have a science and research background (and even then, it’s pretty painful).  He ultimately concluded that considering all of the variables involved, in reality, fluorocarbon monofilament is not “invisible” in water.

Anecdotal evidence (a limited selection of examples which support or refute an argument, but which are not supported by scientific or statistical analysis) by many fisherman suggest that, yes fluorocarbon is less visible to fish than nylon monofilament.  So, is this true?  Maybe…

A lot of folks have reported many types of tests to quantify this (non-scientific tests, but interesting nonetheless).  People have put lengths of same diameter nylon and fluorocarbon in glasses of water, aquariums, in lakes and rivers, and looked at them and photographed them.  The majority of those folks report they can’t see a difference between the two.  Of course they all admit they are not fish under water looking at the materials with the naked eyes of fish.


My own anecdotal evidence suggests that in clear water, steelhead most certainly see fluorocarbon monofilament line when it drifts towards them and they move out of the way from the offering (no matter what it is) well in advance of it ever getting to them.  While I cannot write a peer reviewed scientific paper based on my observations, I’m comfortable saying, in gin clear water….fish can see fluorocarbon monofilament line.

YET, I do construct my leaders from and use tippet material made of fluorocarbon.  Why is that if it is not invisible and certainly costs more?  For me it’s simple.  I guide clients with varying degrees of experience.  And fluorocarbon does give me some advantages. 

Fluorocarbon has higher tensile strength at smaller diameters than nylon.  I want to give clients every advantage I can, knowing full well when they are with me they are in the middle of a big learning curve on how to catch steelhead on the fly rod.  So, it is true, fish are less spooked by smaller diameter line and if I can use a smaller diameter line that is stronger to help a client get a fish to hand, it’s a win win. 

Once someone is comfortable with proper presentation of offerings and how to land a big crazy fish on fly gear, many of the reported advantages of fluorocarbon may not be as significant.  From my perspective, I have a very limited amount of time to spend with any given client to cover a ton of material and get some fish in their hands.  In that setting, fluorocarbon limits some of the issues with presentation error and helps a little with not breaking off fish when making common mistakes fighting and landing these big fish. 

From my personal fishing perspective, at the end of the day, hooking fish still comes down to precise PRESENTATION PRESENTATION PRESENTATION.  In my opinion, the visibility of the line plays very little role in whether I hook fish.  And there a a multitude of other ways we spook fish and shut down a bite before we ever get out lines in the water.  In previous articles we have discussed that fish see a lot in an out of the water that does not even relate to line visibility.  And this does not even account for things we do unknowingly that disturb a run before we even get close to it.  We would be hard pressed to narrow why we are not catching fish down to the visibility of the line we use.  But it can be a piece of the overall picture that also should not be neglected.


To me, it’s more of an issue of making the right kind of presentation in low gin clear water than having an invisible line.  For example, swinging an offering down in front of fish presents only the offering to the fish (not the line), where drifting an offering does tend to present the line and offering at the same time.  And in the case of Steelhead Alley steelhead, they get educated to line drifting at them pretty quickly from the moment they enter the tributaries.

I’ll discuss other topics within this specific debate in upcoming articles.  Until then, if you’re gonna be in northeast Ohio or northwest Pennsylvania on business and want to spend a day on the water or you are local and just want to work on some aspect of your steelhead game…call me!  LET’S GO FISHIN’!

Sunday, October 19, 2014

Fish Vision: Color Underwater

Now that we know what fish see above the water’s surface, what do they see in the water?  Let’s start with color.  

We discussed in the previous article that water has different optical properties than air.  Water is about 780 times more dense than air.  As light hits water, not only does the light bend, it is selectively scattered and absorbed.  Greater than 75% of the visible spectrum is absorbed within about 30 feet.

Here’s what you need to know and think about.  In clear water, the colors we see as red, yellow, and orange are lost first.  “Lost”, meaning scattered and absorbed.  The colors we see as violet, blue and green reach farther, with blue penetrating to nearly 500 feet.  How far light penetrates on a given day depends on the angle of the sun, the roughness of the water’s surface, and how much sediment is suspended in the water (turbidity).

Light intensity plays a big part in how a fish perceives color. Fishing on a sunny day will allow light from the sky to penetrate much deeper through the water column than on a day with clouds. Shiny colors like silver and gold are less effective when cloud cover rolls in, and can become almost invisible without the sun shining, even in clear water. The reason for this is that they reflect the grayness that is surrounding them, instead of the bright rays of the sun. Casting darker colors (like blues and purples) in low light (whether due to cloudiness, early or late in the day, or water with a high amount of suspended sedimentation) often work best by giving your fly the greatest contrast and silhouette. 


***So remember, as the sun sets (or at sunrise), cloudy days, or in stained water, colors like red, yellow, & orange will disappear the quickest. Blue, violet, and green are seen by fish much better in these low light conditions.

Now, what about all of these shiny materials and UV enhanced materials we see for files these days?  Great question!  Glad you asked.

First, there is some research that suggests that fish can sense polarized light (where we humans cannot separate polarized light from regular light).  Polarized light is unique in that it only vibrates in one plane.  I know, blah blah blah, but stick with me here.

When light is reflected off many nonmetallic surfaces, including the water’s surface, it is polarized to some degree.  Your polarized sunglasses block horizontally reflected light from the water’s surface, permitting only vertically reflected light through…thus reducing glare.


What does all of this have to do with fish vision?  It’s thought that fish that can see polarized light use the ability to help them find food.  When light reflects off of surfaces like fish scales, it becomes polarized.  A fish with polarizing vision can more easily make out baitfish and not lose them in the background of the plants and or rocks in the water.  It is also thought that fish with polarizing vision can see objects as much as three times further away.  AND, polarized light is most abundant at dawn and dusk.  Way back in 2001 a great study was done that showed in Oncorhynchus mykiss (our beloved steelhead), polarization sensitivity may provide these salmonids with an improved means of locating prey.  (That’s as crazy technical as I’ll get in these articles. I promise!) Now, this study was in juvenile fish.  There is some research that suggests that mature salmonids lose the ability to see polarized light.  And there is other research that suggests that salmonids regain that ability for a time when they reenter the rivers and streams to spawn.

Now you understand why many companies that make materials for fly tying are manufacturing “Polar” products.  Steelhead may be able to see them better, from further distances, and in lower light.  And this is how they look for food, at least as juveniles.  Think you might want to use this stuff in your flies?

What about all of this “UV” stuff (UV = ultraviolet light)?  It’s similar and pretty simple.  There is research that shows that colors that fluoresce in UV light are visible and distinct for longer distances than regular colors.  BAZINGA!  UV light is most is dominant on cloudy or gray days.  On sunny days, the fluorescence is much less.  So, under the right circumstances, we can take advantage of materials that fluoresce under UV light to gain a more visible and vibrant presentation.


All of our flies are used to imitate something fish feed on.  And at times, it can help to add in materials that can be seen by fish that can see polarized light and it can help to add fluorescent or “UV enhanced” materials to make the fly stand out.  Of course you must also understand that these enhancements could work against you when chasing fish that are in areas with abundant forage.  Fish key in on “hatches” very specifically at times because they are safe.  It is against their instinct to eat something unusual in those situations because it presents more risk to them.  So, you have to chose wisely for each situation.

Hopefully this gives you a concise little primer on why and when we use the colors and materials we use for various fishing conditions.  If you need more help drilling down your steelhead game…call me!  LET’S GO FISHIN’!

Saturday, October 18, 2014

Fish Vision: Above the water

What do fish see?  I was asked this question at a steelhead exposition a few weeks back.  My initial answer was, “That is a much broader question than you might think.”  How fish see out of the water, in the water, and how light effects what they see is has been the topic of study for many many many graduate students and other researchers around the world.  It’s a great question.  And if you can have a basic understanding of a few of these concepts, it really can impact your fishing.


Let’s start with: What can fish see above the water?  First, you have to understand that fish live in water and water has very different optical properties than that of air.  Depending on the angle  light hits the water, a calm water surface can reflect up to 80% of the light hitting it.  And in rough water surfaces, there is tremendous variance in the transmission of light no matter what angle the light hits the water. 

That may sound technical, but it matters.  You are already starting to get an idea of why you can easily approach fish in some water and they are very spooky in other waters.  Surface movement of the water and the angle at which light hits the water plays a big role in what fish see out of the water.


The next concept you have to understand is that light bends (or refracts) when it enters the water.  So?  So, that allows each eye of the fish to see a certain area above the water that works in a different way than we normally see things.  Nearly everything a fish sees above the water appears in a circle (more of a cone really).  This circular window is smaller for fish close to the water surface and becomes larger the deeper the fish is in the water.  Outside of the window, the surface of the water appears as a mirror, reflecting the bottom. If the surface is choppy, the mirror effect is reduced.  In rough water this circular window is broken up and light is transmitted through continuously changing patterns. 

Yes there is a lot going on here. But you just need to be aware that fish see in a circle or cone above the water.  The circle is bigger for deeper fish and smaller for shallow fish.  You want to stay out of that cone.  To do this, you need to be back away from the fish and low to the horizon.  And there are other things that can help.  Low light conceals you even more and rougher water is further helpful.  And now you can see why fish in smooth water on a sunny day just scatter as you approach them.  


I tell folks everyday, “Know where the fish should be for the day’s conditions and fish for them in those places.”  Do not get fixated on fish you can see, rather fish the places they should be.  And those are places you cannot normally even see the fish.  Now you better understand why the fish also struggle to see you if you approach them correctly in these places.  That is a combination that makes for a great day on the water.  It also helps you understand how precise things have to be on those occasions when you are sight fishing.

Are you ready to take your steelhead game to the next level.  I can help you with that.  Call me.  LET’S GO FISHIN’!