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’!