Get more out of your Graph

Fish, Lies and Video Screens…are you getting the most out of your fish finder?

See if this little scenario sounds a bit familiar to you:

You’re out on the water and you’re marking a bunch of fish on your graph. The fish are absolutely thick beneath the boat and you’ve got your gear plowing right through them…yet…you’re not getting bit. You’ve tried altering the depth of your lures to no avail and you have also been through the “trying everything but the kitchen sink” routine and have still yet to find something in your box that the fish want to eat. You can see the fish down there but it’s like they’re collectively flipping you the bird. Looking at all those schools of fish pass under the boat is kinda like the movie JAWS 4…so bad, you just can’t bear to watch anymore.

Believe me, this is the kind of stuff can get in your head, too. To skunk out on a day when there are tons of fish around has a tendency to eat away at your confidence and keep you up at night, pondering what you could have done differently.

But don’t take it too hard, amigo. You probably didn’t do anything wrong except believe a big fat lie.

Lowrance Graph

This may or may not make you feel any better, but here it goes anyway…your fish finder may have been lying to you. Yep, you heard me — that little black box on your console, the one on which you spent a small fortune and rely so heavily upon – it’s been telling stories.

Of course, I’m not calling all depth sounders liars here, nor do I feel that they vindictively mislead, but there are things you need to know about how your unit works before you can trust it. The biggest problem with many fish finders is what is often called the “fish I.D.” (or something along those lines) feature. This is a function that, unfortunately, has become quite popular on most LCD graphs these days.

With the I.D. mode turned on (the default setting on many units), submarine objects that the depth finder picks up between the boat and the bottom are displayed as cute little fish shapes that look a lot like goldfish crackers. The only problem is, a depth finder cannot always tell a fish from…say…a weed bed, a submerged log, a thermocline or…a mermaid. A good way to illustrate this is to go from trolling speed to full throttle while watching your finder. Your entire screen will get inundated by signals your transducer is reading from the boat’s cavitation bubbles…it will go mostly black. When you have fish I.D. on, those bubbles will often register as, well, fish.

Get Naked!

I can say that the technology has dramatically improved and that the I.D. feature on newer units is getting better and better all the time. However, if you really want to know what’s happening below the boat, you have to turn that function off and learn to interpret the signals without the goldfish crackers.

Most units (except for some of the less expensive models) allow you to do this. You may have to scroll through several sub-menus until you run across the right screen and, on some models, you’ll need to switch from the unit’s basic automatic setting to the manual one to override the I.D. system.

Initially, you may feel a little naked without I.D., but you’ll eventually get the hang of it. When your depth finder’s signal bounces off a fish in the non-I.D. mode, it will register as an arch-shaped mark on the screen with the apex pointed towards the top of the display. All the other stuff like bubbles, submerged debris, reefs, weeds, etc. won’t show up looking like arcs. With a little practice, you can really begin to interpret what you’re looking at with greater accuracy with I.D. turned off – which will, hopefully, help keep you from trolling back and forth over that school of “fish,” which actually is nothing but a bunch of grass along the bottom.

If the transducer’s signal doesn’t hit the fish square on, or the fish makes a sudden movement just as it’s being “painted,” you may get a variation of an arc, but it will still be something that looks a lot different from the many non-fishy things down there. Fish that are moving with you will show up as horizontal lines and your sonar may also return partial arches — fish that were only “painted” by your transducer’s signals briefly before swimming out of “sight.”

Things get a little more tricky when schools of fish are tightly packed together, because the transducer can’t always separate each individual fish on the screen. In those instances, you may see just a big, dark ball shape. When you pick up a dense blob like that, you can be pretty sure you’re looking at fish if it’s suspended above the bottom. When fish are schooled up right on the bottom, it can be hard to tell what’s rocks and weeds and what actually has fins on it. Luckily, today’s color units have the ability to differentiate – through color shades – between solid structure and live critters much better than the older grayscale models.

Practice, Practice

To become proficient at using a depth finder, you just have to get out on the water and run the thing. Also keep an eye out for seminars at your local sportsmen’s shows and boat dealerships. A lot of the big name marine electronics manufacturers run training classes throughout the year which will take you through everything like ping speed, sensitivity settings, etc.

Eventually, you’ll get a better feel for what you’re looking at — and you’ll catch more fish as a result. The only bummer is, there will still be days when you see a million fish on the screen and you won’t be able to get them to bite…only now you’ll know that they really are fish!


  1. says

    The Goldfish crackers on my fishfinder screen usually end up in my fish box :) or at least when presenting those Goldfish crackers with the right bait and the depth the goldfish crakers like to feed can have some pretty positive results. I belive my fishfinder when I see the little and big Goldfish crackers on my screen :)

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