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The Eyes Have It

by: David Coulson 3/21/2013

I’m a lifelong student of many subjects, especially when it comes to doing what I love, fishing.  It’s my belief the more you know about something, the better you’ll be at it. Consequently, I’m constantly studying and practicing fishing.

Recently, I caught up on my backlog of fishing magazines, not sure how many, but I estimate the stack was a couple feet high when I decided to work my way through them, BASS, In-Fisherman, American Angler, Salt Water Fly Fishing, and others.  I finished that task last month, and dug into my library, pulling out books long overdue for a read. Since then I’ve worked my way through four texts on the workings of fish, “Where the Fish Are”, “Knowing Bass: The Scientific Approach to Catching More Fish”, “What Fish See”, and “How Fish Work.”  None are definitive works, but each makes some good points. Of the lot, “Knowing Bass” and “How Fish Work” are most worth reading in my opinion.

Being primarily a fly fisher, most of my “lures” are designed primarily to stimulate the fish’s sense of sight, and secondarily sound and pressure.  Thus, I’m extremely interested in understanding, what fish see and how can I use that to design better flies (or lures).
My first pass through these books got me thinking, but I’ll admit I don’t fully understand all that I read, at least not yet. Over the next couple weeks I intend to reread those chapters pertaining to vision and supplement it with a bit of on-line research and research journal articles.  That will either clear up or totally muddy the waters on the subject.

However, there are a few insights that I’ve gained.  For some of you, this may be old hat, for others something new to think about, either way, writing helps clarify my thinking. First off, most fish see very well.  How sharply depends on a couple of things.  Such as, where is the object located in the field of vision? To the side only one eye views the object, where directly in front the fish has binocular vision like ours.  Then there’s the issue of water clarity and how far away the item is.  Any particulates in the water will make for a fuzzy view (think fog).   And the further away, the more the image is dimmed due to the filtering effects of water.

Second, many fish appear to be able to distinguish colors.  Although, how colors appear no one is exactly sure for several reasons.  First, depending on the species, the number and types of cones sensitive to colors differ.  We have three, bass two, and some species four (thought to have UV detection).  In the case of bass, studies indicate they are readily able to distinguish between shades of green, yellow, orange, and reds.  But they struggle with shades of blue. 

The other issue with color is the filtering effect of water.  In clear waters, such as the oceans the further away you are most of the warmer colors are filtered out, leaving just shades of blue and green.  However, is freshwater with some organics, primarily greens are left.  In muddied waters, with limited visibility the warmer colors, red, yellow, and orange remain, blues and greens are filtered out  (look black).

A common theme that occurred was the importance of contrast.  Simply, if a fish isn’t able to pick out your lure from the background, it won’t be seen by the fish.  Plus, in the case of the sunfish family, there is evidence that objects that don’t move tend not to get noticed, even if they’re fully edible.

Other “light” topics discussed included florescence, phosphorescence, and polarization.  Simply, there’s a lot to think about and that’s before trying to incorporate other senses especially sound and pressure into the mix. As I work through the material I’ll try to share some of what I learn with you.

Of all the items above, the one that strikes me as being most important is contrast.  Your lure/fly must stand out from the background.  Many of us unknowingly figure this out through trial and error.  For example, over the last few years I’ve found that a black and chartreuse Foxee Clouser is very effective for carp in stained water (less than two feet).  In these readings it was pointed out that black tends to show well in muddied waters, and when combined with a florescent color, such as chartreuse contrast is maximized.  That goes a long way to explaining the effectiveness of that color combination over others under muddy conditions.  Carp can see it better than other colors.  And I figured out by trial and error what the texts suggested would be a good choice. 

So my hope is all this reading will help me choose effective flies with a little less trial and error. As my vision clears on this topic, so to speak, I’ll share my thoughts in greater detail over the next few weeks.

Blog content © David Coulson
Member comments
Coyute, CO   3/21/2013 12:03:08 PM
Good blog.
jshanko, CO   3/21/2013 2:16:26 PM
Interesting data in your presentation. I believe I've read something of this before. Can't wait to see how you put this info together and corelate it with their other senses.
tracks, CO   3/21/2013 3:30:42 PM
Good things to think about and put to practice Dave.
OldMikkDale, CO   3/21/2013 3:38:45 PM
Great blog, I will be looking forward to future ones on this subject. Thank you for doing it.
Bassackwards, CO   3/21/2013 5:50:25 PM
I read that article in Bassmaster as well. Very interesting. Im not sure on their color scale, but certain colors have always been solid producers. Purple, greens, black and blue, have always been staples for me. I think that it may have more to do with conttast than colors, but thats just my opinion, because the deeper you fish,the more color fades away.
David Coulson (Flyrodn), CO   3/22/2013 10:41:05 AM
Thanks for the compliments. Interesting point that I'll cover more later. In crystal clear waters (oceans) blues/greens remain in deep (over 50 ft), but in most fresh waters and stained waters the blues are abosbed with much depth. Consequently, fishing deep with blues, purples, and black, they will all appear as black. Further, Bass don't appear to have cones (in the eye) sensitive to blues. So to bass it is likely in most waters, especially with any depth, they will not be able to distinguish between black, and shades of blue or purple.
JKaboom, CO   3/24/2013 4:39:30 PM
Great BLOG it's funny, I put off reading it because I thought it was about walleye fishing
David Coulson
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