The super clear water conundrum

[Al Agnew]

In my three day float I just reported, I was fishing water that had at least 12 feet of visibility, and it got me thinking about the problems with super clear water.  There was a time. many years ago, when I thought you had to use very light line and small, finesse type lures in those conditions.  Growing up fishing Big River, which was never that clear, I knew you could use heavier tackle and bigger, noisier, more water-displacing lures to great effect when the water had 4 feet or less visibility, but on the rare occasions when I'd fish a creek like Huzzah, I was basically freaked out about the clear water.  Finally, one day I decided to fish Huzzah (or was it Courtois) and just use the same stuff I used in the murkier streams.  It worked...well, at least some of it worked.  I've never had good luck, and don't have confidence in my homemade crankbait when the water is extremely clear, but the other stuff I used on Big River--the twin spin and topwaters--worked just fine.  I also ditched the ultralight tackle and 4 pound line, and just used the same 8-10 pound test stuff I use elsewhere, with absolutely no problems spooking fish.

So I learned that smallmouth aren't really line-shy, and they are the same aggressive fish, looking for a good meal, in clear water that they are in murky water.  The difference is simply that their "zone of awareness", and zone of "run and hide", is far larger in clear water.  In other words, they can see danger a lot farther away, and they instinctively know that danger can see them a lot farther away, and act accordingly.

This is the second year in a row that I've had much the same experience on my secret creek, by the way, in that I caught far fewer fish in the big, deep pools than in the shallower pools and runs.  Now...I can come up with several reasons for this.  Maybe anglers are fishing those inviting pools a lot harder.  Maybe the fish in those pools, lying deeper, are just not active enough to feed.  Heck, maybe for some reason the otters I saw can catch those fish easier in the big pools, though I doubt that.  But while fishing that air-clear water, I came up with another, rather counter-intuitive reason why those pools don't produce as well.  But to explain it, a little physics is in order first.

The water surface acts as a mirror from below as well as above.  If you, or a fish, is underwater looking up, past an angle of 48.8 degrees to the water surface, light is reflected off the surface instead of going through it, and the fish sees a reflection of what's in the water past that point, and not what's above the water.  But if the fish is looking up at a steeper angle, more perpendicular to the water surface, the light passes through the surface and the fish can see what's above the water.  But the kicker is that light rays "bend" as they come through the surface, and from either above or below, you see a distorted view of any object.  To us, looking down into the water, the farther away the object is, the more it appears horizontally flattened, because of those bending rays.  To the fish, the same thing happens.  But what's more important to the fish is that because of those bending rays, things above water can be seen much farther away.  

This is the highly simplified version, because it supposes a perfectly flat water surface.  a ruffled surface from wind or current will distort and obscure the sight picture the fish gets.  But keeping it simple for a bit longer, if you're underwater, your eyes are two feet under the surface, and you're looking up, you can see through about a 4 foot diameter window at the surface (it's a round window, by the way).  Stuff that is close to straight up above that window is seen with little distortion, but as your vision approaches the edges of that window, stuff becomes more and more squeezed and flattened.  Still, you can see a little bit of anything that sticks up higher than about a 20 degree angle from the water surface.  (Actually, theoretically you could see anything within about 10 degrees, but at the edges things are squeezed so much that they are basically almost invisible.)  So, you can see a guy in a canoe that's at least 13 or so feet away, probably can see his head a little farther.

But as you sink deeper into the water, your sight window grows bigger.  At 8 feet deep, like some of the fish I saw swimming around in the deep pools, the sight window itself has a diameter of more than 16 feet.  Then you add the greater angle of vision above the water, and the fish can see that same angler in the canoe more than 22 feet away.

Now, consider one of those deep pools.  Very little wind, but just smooth distortions in the water surface from slight currents.  As the water surface tilts from the smooth distortions, the fish can sometimes see a little less far above the water, sometimes a little farther, as the angle of refraction changes in relation to the fish's eyes.  But the reality is that the deeper the fish lies in very clear water, the FARTHER it can see above the water surface in those pools.

On the other hand, a fish lying in shallow, still water has a smaller sight window and can see somewhat less far above the water surface.  Basically, for every foot of depth the fish lies in still water, you can approach that fish at least a foot closer!  But fish in shallow water seldom lie in STILL, shallow water.  The more wave action, from wind or current, there is, the more obscure and distorted the fish's view above water gets.  And YOUR movements, casting or just fidgeting around, blend into the constantly moving water surface.  So, strange as it may seem, you are far more visible to a fish lying in deep, still water than you are to a fish lying in moving, shallow water.

So, those fish in those deep, still pools could see my canoe bottom (underwater) at least 12 feet away (and probably a lot farther than that...I could see the bottom even in pools I guessed at 15 or more feet deep!), and they could see ME, above the water and casting to them, more than twice that far away.  Probably, if I was within 30 feet of them, no matter how quiet I was being, they knew I was there as soon as I made a movement.  But a fish lying in shallow, moving water, while it could still see my canoe bottom the same distance away, couldn't see me as easily unless I was close enough that my whole bulk covered a lot of the little wavelets.  So the fish's above water zone of awareness, 60 feet in diameter or more in the deep pools, might only be half that or less in shallow water.

The difference in murky water is that the fish can't see through the WATER nearly as far.  If it's lying four feet deep in water that has four feet of visibility, it can't see a whole lot farther than that through the water, so its above water zone of awareness can't extend for a whole lot more than about 15 feet or so, no matter what.  If it's deeper, it can't see far enough through the water to reach the outer edges of its sight window through the water.  If it's shallower, its sight window decreases.  So you can approach that fish more closely without being seen, and then only its other senses can detect you.

Basically, if you are totally stealthy and stay low, in clear water you probably still need to make casts that are at least 30 feet long if you're casting in shallow, moving water.  But those casts have to be far longer in the deep, still pools.  So maybe I wasn't catching fish in those pools because they knew I was there.  Or maybe it was still due to the fact that if a smallmouth is hanging out in 8 feet of water, it's not really looking for food.

So...smallmouth in ultra-clear water are naturally more wary of predators.  They can see farther, both below and above the water surface.  They might tend to stay deeper just for a bit more security, thus having a bigger sight window.  So it can tougher because of those factors.  Now add in some more factors...

Smallmouth can not only see farther in that kind of water, they can see BETTER.  Which is why anglers often think they have to use lighter, smaller diameter line in those conditions...the fish can see the line better.  But in ultra-clear water, I know I can see fishing line, no matter how thin it is.  So can the fish, which is why I don't think line diameter, within reason, makes much difference.  You can't tie a lure onto 80 pound test braid and expect to catch a pile of fish on it, because it is SO noticeable and intrusive that the fish are bound to be turned off by it...it's as obvious as the lure.  But the difference between 4 pound mono and 10 pound mono isn't very significant to the fish's view.  Neither overwhelms the fish's notice of the lure.  They can see both, almost equally as well, but neither matters to them if they are attracted to the lure.

But...smallies are highly attuned to their prey.  Our lures don't really resemble their prey all that perfectly (except for the Hi Def Craw, maybe).  They always have negative cues, things that don't look, smell, move, or feel natural.  But often enough, the bass ignores those negative cues because the positive cues are more noticeable.  However, in clear water, the visual negative cues are more obvious.  If something doesn't look real, it needs to have some kind of other positive cue to overwhelm the negative.  In my usual style of fishing, I let fast movement and often splashy movement trigger the bass's instinctive attack response BEFORE it can examine the lure closely enough to see the negatives.  So I can get away with using lures that don't look anything like the natural prey if sitting still--buzzbaits, twin spin, walk the dog topwaters--because I keep them moving fast.  If I would go to soft plastics fished much slower, I'd want my soft plastics to be more "natural" in appearance.  My only real color consideration in very clear water for slowly fished lures is that they blend into the bottom just like natural smallie food does.  And even so, I'd fish them faster than many.  If the bass has the time to sit and examine a lure sitting on the bottom, it has more opportunity to see the negatives.

So while it might be tempting to fish the bottom of those big, deep pools, it probably wouldn't be as productive.  Or maybe I just fish the fast stuff because I have more fun that way, and others could do well with slow stuff in those pools, but I doubt it.

I know this is a long-winded post.  I hope it was worth reading, and I look forward to hearing others' thoughts.

[Al Agnew]

Just thought of another thing about fish in clear, shallow water.  They so often lie up against cover.  While the cover hides them from predators and prey alike, it can also hide you from them.  If a rock the fish is lying against sticks up high enough to block out part of its sight window, and you're behind that rock, you obviously can't be seen.  If I see a big rock that might hold a fish, I always cast well past it, and one of the reasons to do so is that the fish lying on the far side of the rock will be less likely to know I'm coming.

Which brings up another thing I always do in very clear water...I never cast TO a spot where I think a fish might be lying.  I always try to land my lure at least four or five feet away.  I seldom cast to the bank, but about five to ten feet away from the bank.  Never to a good log, but past the log or off it a few feet.  In murky water, I want the lure to land very close to the fish, or at least come by it very closely.  In clear water, where the fish will probably be a lot spookier, a big lure landing on its head scares it silly.  But land that same lure a few feet away, and the fish looking for a meal sees it easily and often goes for it.  Your zone of attraction with your lures is far wider in clear water.

[Mitch f]

Great thoughts...

I know that fish in a shallow riffle are there for one reason only. They are less spooky, and will come from a greater distance to attack their prey or your lure. I've also many times, as you say, had worse luck after the riffle turns into a deep hole. The cone of sight you described makes a lot of sense. 

[ozark trout fisher]

Definitely worth reading. I love smallie fishing this time of year, and into October, but it's definitely a different challenge than it is in, say, June. 

I also tend to prefer the faster water and skip the deep, "fishy" looking pools more often than not. The only problem is that many of my new streams around here (NW Indiana) are really slow for long stretches, so you pretty much have to pound the glassy, still pools or go home. I need to get better at that game if I'm going to be as successful here as I was in the Ozarks. 

Of course, there are some faster, more turbid waters I can hit when I need a little break from having to try to be a stream-ninja. But mostly I don't mind it, as someone with a background spending a lot of time stalking spooky wild trout in Missouri creeks, it's not all that different. 

[Greasy B]

I found that Identifying the size of the spook zone is a small stream is pretty easy if you watch the suckers react to your advancing profile. Suckers are a better indicator than bass being much more numerous.  I agree with your reasoning but It's seems contradictory that I see fewer fish fleeing my spook zone in deeper water, maybe their just not very spooked. 

[timinmo]

I don't know anything about the cone of vision, I don't question your reasoning.  I am sure they go to fast shallow water to eat, as mentioned, and I believe they go to calm deep water to rest.  Often if you can find the deep water near the fast shallow you're golden but I think everyone with some experience agrees with that.

For what ever reason it seems that this time of year the fish are spookier.  Light line may not matter but I do believe long casts help as does a stealth approach.  In any case this time of the year they do not seem as aggressive as some other times, but they are still there and can be caught obviously.  Tactics may need to be adjusted.

 

 

[Daryk Campbell Sr]

Curious on colors.  So, you mentioned you like to match the bottom.   I agree with that, as you want to imitate the prey in said area.  But, it is also well known that albino prey is often easily seen, therefore eaten.   Brings up the question, why try hard to be camouflaged, shouldn't we be using lures that stand out?  Curios to read all thoughts.  

[ozark trout fisher]

3 hours ago, Greasy B said:

I found that Identifying the size of the spook zone is a small stream is pretty easy if you watch the suckers react to your advancing profile. Suckers are a better indicator than bass being much more numerous.  I agree with your reasoning but It's seems contradictory that I see fewer fish fleeing my spook zone in deeper water, maybe their just not very spooked. 

Interesting idea, I've never thought to try this. 

[Mitch f]

The straight line distance to the fish is the same if you throw your spook directly over a fishes head in 5 FOW, or throw it 5 ft away from the in 1 FOW. The difference is, they should be able to have a clearer picture of the lure form down deep, as Al says. I was blown away up on the Upper Mississippi how fast they could close the gap and get to my topwater from 5 feet away. It was a total reaction bite. But when I dropped one on their head you could see the wake from them being spooked. I think the key to getting bit is the fish reacting without ever getting a good look when you're fishing topwater. As far as colors Daryk, I very knowledgeable friend gave me this advice on topwater. Use white all summer then switch to broomstick brown in the fall. I've found that all colors work pretty well on topwater if your making enough ruckus. When you're twitch-twitch wait type topwater fishing, maybe the color means a little more.

[Seth]

Clear water is my favorite. Only need maybe two lures

5 hours ago, Daryk Campbell Sr said:

Curious on colors.  So, you mentioned you like to match the bottom.   I agree with that, as you want to imitate the prey in said area.  But, it is also well known that albino prey is often easily seen, therefore eaten.   Brings up the question, why try hard to be camouflaged, shouldn't we be using lures that stand out?  Curios to read all thoughts.  

My favorite clear water bait stands out like a sore thumb, but the bass love it!