Finding bottom structure

[pikerliker]

How do I find bottom stucture in lakes that I'm learning? An example is you might here somebody say "find where the bottom changes from gravel to sand" or "from muck to sand", or "where the weeds are coming off a break", etc. I have a Marcum LX1. Is there a way to use this to determine what kind of bottom I am looking at? Is there another way to determime what kind of a bottom I'm over? Any help is appreciated.

~piker

[winona walleye]

the marcum im sure does tell you the bottom structure, i do not have a marcum but i do have a vexilar and in the manual it gives hints on hwo to read the bottom. a strong signal (usaully red in color) means that the bottom is hard, usually gravel or rocks, if there is some week signal (orange or green) it means that there is a layer of much above the hard surface, the best way to learn is to just study these things each time you go out see how the bottom line changes on the screen. im no proffesional myself but i think im startin to get a hang of it

ww

[harvey lee]

The best way I have found is to buy a camera if that is a option.It will open up a whole new world of looking at the bottom and telling what fish is down there,weeds,everything.I used to say I would not go fishing without my Vexilar,now I say that about the camera.Great item along with the Vex for fishing new lakes.Sometime when it works we could go to the lake and I could let you use my camera and you could see how it works.Maybe Washington or one of the lakes south of you.Always open to a day on the lake.

[Woody Erickson]

One way to determine to hardness or softness of the bottom, is to use a tape measure. Just extend it down the hole along with your LX1. You should be able to watch it going down with your LX1. When it comes in contact with the bottom, you should be able to tell if it is rocks, sand or mud. Eventually, all you will need is your LX1.

hope this helps,

[delmuts]

the idea of using a camera is right on.( if one is available)other wise you can try using your locator in clearer water where you can actually see the bottom, that way you can see how it shows on your screen. the info is there. you just have to learn how to understand it.

[gonefishin11]

When I am looking for structure, I prefer to shoot right through the ice with my vexilar. Tall weeds are easy to see on the vexilar because they will show up as 4-8' of red coming off the bottom. You can find the weed edge by moving away from shore, which generally means into deeper water, and using your vexilar or marcum to find where the weeds stop.

I have been using a vexilar only for this for the past couple years and I finally bought a camera. I tried this technique last night, found the weed edge, drilled a hole, put the camera down and it confirmed what I suspected.

Hope this helps a little.

[Jim Hudson]

Piker

This is a great question, and a lot is written about the subject, but sometimes it is hard to understand... I remember trying to figure it out at first too!!!

Anyways, the best way I have found to find the change in bottom composition is to search it out during open water... A lot easier, and then I just mark these spots onto my GPS.

But if going alone on the ice with a flasher, the key is to watch how your unit is marking the bottom. A really hard bottom, such as rock, gravel, etc will show up on your flasher as a crisp red color and you will not have to use as much gain to read bottom... As you move over softer bottom, the band of red that marks bottom on your flasher, will start to enlarge on your display. Also, the more gain you have to give your flasher, usually means the softer the bottom. As you see your flasher do this, you know you found a transition...

But to really see this structure and the composition, one needs a camera. You then can see the distinct change or also see if your fishing over boulders, rubble, sand, etc etc... The flasher will only give you a clue as to if the bottom is harder or softer, but to find what the actual material is, a camera is key!!

Just some little tips, and hope it helps out.

[Surface Tension]

Both Vex and MarCum will show you bottom content. Soft bottom, mud, mud over hard bottom, gravel, rocks and weeds. Your MarCum will do this as is, start out with just enough gain till you read bottom and slowing increase the gain and then back down. Doing that will give you an indication of what you have down there. If your using a Vex its the same procedure but if your in shallow water using a FL8 your going to want a suppression cable otherwise your signal will be too hot. With an FL18 just turn on the suppression.

The tape measure although simple works very good with no interpretation. Bad side is you have to keep it warm for obvious reasons and then dry it out at the end of the day.

Knowing the lake and what depth the weeds lines stop at is helpfully. As a rule clear lakes = deeper light penetration so deeper weed growth. That can change though as to what type class lake you on. Fertile lakes will have a heavier weed growth then your northern infertile lake.

As simple as it sounds, look at the shoreline. For example you can get an idea if your in a muddy shallow area of maybe a boulder slide just by looking at the shore.

Lake maps and a GPS will get you on structure and even lake bottom content in a hurry with minimal searching.