Do depth finders Find Catfish

[Drawout]

Ive heard that a depth finder detects scales on fish and thats how u get a reading,If this is true then how do they find catfish or do they ? "Sorry If this is a stupid question":confuse:

[RamRod]

That's not a stupid question at all brother. It's actually a very good question that I personally asked DH not long ago over a phone conversation with him. When he sees this question, I'm sure he'll be able to answer your question and make you understand better than I could explain it. But yes you can tell the difference between scaled and non-scaled fish with a fish finder.

[catcam]

It's all about the whiskers!
They should- my depth finder finds things that I know are not fish but appear so on the screen- large floating debris and you think Jaws is underneath the boat.

[Dwednuts]

Depth finders are great tools for finding catfish. I look at it this way, when you find the right type of structure and you see fish arches in that srtucture, chances are you have found the cats you are looking for. You need to be able to read the structure and it's proxcimaty to a deep hole or channel, to determine what type of fish are in the structure.

[Arkie55]

Depthfinder is the best tool on my boat. I not only use it for finding holes and structure but with practice you can determine bottom type (hard, soft, rock, ect...) structure type, (stumps, tops, trees, ect) and locate and catch the fish. That's right. Many times I have been checking a hole and find good arches positioned on structure that indicate they may be active. I've then set the boat in a position to effectively fish that structure and those fish. Lots of times within 5 minutes of presenting the bait I've had a fish on.

There are many others here that know a lot more about reading their depthfinder than I do but I will tell you this. Set it up to show arches and not fish drawings. Then learn to use the zoom feature. Get the "Greyline" feature too. The things you can see and learn with these three features set up and running will really improve your fishing.

[DeerHunter01]

Drawout

Look at this see if this helps you any if not I am sure JW can explain the entire thing to you !!

http://www.catfish1.com/forums/showthread.php?t=14249

[BIG-G]

I don't see how you can shed any more lite on the topic DH! LOL!

[katcatchingfool]

thanks deerhunter that was very informative ive been wanting to get another depthfinder

[Drawout]

Thx alot all great responses and DH that is very detailed:big_smile:

[Flatheadhunter33]

Ive heard that a depth finder detects scales on fish and thats how u get a reading,If this is true then how do they find catfish or do they ? "Sorry If this is a stupid question":confuse:

Not a dumb question at all Johnny. I friend and I were wondering this very thing. Now we have all been educated. Thanks.

[catseeman]

Thanks for the lesson . depth finder 101 :big_smile:

[ShilohRed]

Depth finders are great tools for finding catfish. I look at it this way, when you find the right type of structure and you see fish arches in that srtucture, chances are you have found the cats you are looking for. You need to be able to read the structure and it's proxcimaty to a deep hole or channel, to determine what type of fish are in the structure.


Man I wish I had read this post before going fishing this morning. Fishing a deep water tree. It was in 35ft of water. Also this was off a deep water point. along a creek channel.
Depth finder showed fish. Well after 2 blues, 5 channel cats, 2 crappie, and 4 white bass left it.
JW what was I doing wrong to catch all that in one tree?

Also depth finder works on blocked signals. Anything that blocks the signal will return a signal. Scales have noting to do with it. Fish, sticks, anything that is floating under water will show a return.
Pete

[bluejay]

Great article. Learn something new every day.

[777]

Johnny, I think I seen posted on here before the only dumb question is the one not asked. Im glad you asked this question. That is some excellent info DH shared. I learned alot THANKS.

[CBH]

Whoever said that you can tell the difference between a scaled and non-scaled fish with a depth finder is "mistaken"!! Maybe it was meant to be a joke!!
The top of the line depth finders show the fish as arches of different sizes. Color units will help you to detect the fish easier, especially if the fish is right on the bottom, but none of them will help you to determine if its a catfish or a gar!
The only way to see what is actually under the boat is to catch it or see it somehow. An underwater camera, such as an Aqua-View, would be a very interesting and valuable tool to use around log jams!!

[DeerHunter01]

Whoever said that you can tell the difference between a scaled and non-scaled fish with a depth finder is "mistaken"!! Maybe it was meant to be a joke!!

You know I just love it when someone comes on and makes a bold statement like this, it was not a joke and you believe what you want and I will too. I hope this helps

D/H

[loanwizard]

Whoever said that you can tell the difference between a scaled and non-scaled fish with a depth finder is "mistaken"!! Maybe it was meant to be a joke!!
The top of the line depth finders show the fish as arches of different sizes. Color units will help you to detect the fish easier, especially if the fish is right on the bottom, but none of them will help you to determine if its a catfish or a gar!
The only way to see what is actually under the boat is to catch it or see it somehow. An underwater camera, such as an Aqua-View, would be a very interesting and valuable tool to use around log jams!!


Uh.... no it is no mistake. I bought a lowrance 135 just like DH's. I cannot yet operate it as well as he can, but his is set, and I have personally witnessed it, so that there is a marked difference between a scaled fish and a non scaled fish. BTW the X135 has 4000 watts of peak power. You see the banner at the top of this site? That's DH, and as jealous as I am of him, he caught that fish after he marked it and a few others. Careful how you say something on here. I am sure you are quite knowlegeable and it honestly amazed me too the first time I saw it.

[Drawout]

Dont get to fired up Dh, i started this thread and u answered my question perfectly thats all that really matters. :cool2:

[CBH]

Alright......I'll just have to see it to believe it. I've been using Lowrance depth finders for years, and I've been in many boats with very good units, but this is the first that I've ever heard about detecting a fish with or without scales! Didn't mean to ruffle feathers....it's just hard for me to believe! It would be cool if my LC X-17 could do it!!

[Doctor]

Drawout, Don't mean to hijack your thread but I would like to respond to CBH.

Using a Lowrance LMS350A in manual mode and setting it up for a double echo method it is very possible to tell scaled from nonscaled fish. In the second echo only anything hard will reflect back a positive signal to the unit, so any fish that has scales will reflect back, any non scaled will not. Gets confusing but here is what you have, as an example your fishing 30 foot of water, i'll set up my unit in manual mode for 65 foot depth of water, it will paint a picture on the screen at 30 foot, if the bottom is hard then there will be another picture on the screen at 60 foot or twice the depth, a soft bottom will not return anything, if your targeting a Catfish that is sitting behind a large boulder in 30 foot of water the boulder will show up at 30 foot along with a fish arch at 30 foot, but that same boulder will also show up at 60 foot but the Catfish having no scales will not show up at 60 foot.

I'm getting ready to upgrade to a new Lowrance color unit so I'm sure that a lot of things are going to be different for me when I start using this newer unit.

Doc

[CBH]

Thanks Doc. That will give me something to play with the next time I'm on the river! One thing that I've dicovered in the years past, is that a lot of guys have no idea how to run their units in the manual mode. Many just turn it on and let it go! The one thing that's certain is that you have to run your depth finder in the manual mode if you want the most out of it!! I've been trolling for muskies for many years, and a good depth finder is a must, but this catfishing is fairly new to me. Hopefully I'll be able to take advantage of this "second echo" trick to help boat more cats!

[dcaruthers]

Thanks for all the info. What Fish Finder would you guys put on your boat if you had 2-3 hundred to spend. Any where would you purchase it?

[DeerHunter01]

If I was buying a new depth finder and could not spend alot of money then I would get the X135 thats just me, it can be bought for $399.00 now days it used to run about $525.00.

[ShilohRed]

If I was buying a new depth finder and could not spend alot of money then I would get the X135 thats just me, it can be bought for $399.00 now days it used to run about $525.00.

DH we know what model you would love to have. LOL
And mine is working great.
Pete

[navigator]

I went to a BASS class several years ago and a guy gave a lesson on depth finders and he said the most important thing was the number of pixels the depth finder has, then I think the power.

he went on to describe as well as you folks have that manual mode is best and you have to learn how to use the thing.

I just bought the Bottom Line 480 Max with 480 X 480 Pixels with 3200 watts of power for like $150 from Bass Pro.
It has temp as well.

I haven't really learned how to use it though but it seems user friendly.

[blackwaterkatz]

Per the topic header: I managed to catch my personal best bluecat after marking him in around 32' of water, anchored upstream, and had him on withing a couple of minutes of casting cut shad, before I could even get a 2nd line in the water.

[Doctor]

Oh Yea.................

http://img414.imageshack.us/img414/7277/lowrance1ld.jpg

Doc

[ShilohRed]

Oh Yea.................

http://img414.imageshack.us/img414/7277/lowrance1ld.jpg

Doc

Doc you could have bought a good one for what that one cost. LOL
Pete

[sds888]

all I can say is WOW what I once didnt know is now going to get me to go a try to see if I can see the same thing
Stephen

[redneckradtech]

DH wanted to read your thread but not opening. I hope to learn more about using sonar to find catfish over scaled fish.
Lets reopen this on it is good talk.

[redneckradtech]

Can't find the info that was available. That would have been a good sticky

[DeerHunter01]

For some reason that page is not showing I am not sure where it went too, but look under CATFISH PUBLICATION and go to Outdoor Articles and look up the X135 report that I did. Its close to the same one, just the other had lines drawn on it showing scaled or non-scaled fish.

[bigBB]

what is the title of that right up? looked in the thread but couldn't come up with it.. thanks

[DeerHunter01]

The title to that thread is X135 Fish Finder ...

Here is the short cut to it.. Click Here (http://www.catfish1.com/forums/showthread.php?t=69177)

[dinger66]

i have an lcx 480 will i be able to do this with this model ? i was told by lowrance that it could not tell between the two ,just stateing what they told me.

[DeerHunter01]

dinger66:

What Lowrance told you is true, they are not going to make a statement like that , 99.9% of them have never fished a day in there lifefor catfish. 90 % have never been on the water and used one either, I know this to be a fact, I have talked to Lowrance several times, and I am on the VIP program with them.

They have a great unit, what I am telling you is what I have found to be true for me and several other people, when we mark a fish with the echo it never bites, and you never seem to catch it ever, But when I mark the fish with out the echo its seems to knock the pole off the rod holder, this has happened alot of times for me and other people, this is just my opinion with this , so you can either take it or not. This is just information that I have found to work for me. Some people believe it and some don't, and it really don't matter to me if they do or not cause I can put fish in the boat that don't have that echo and I can sit all day over echos and not get a hit.

Any unit that is at least 4000 watts and above and 480-x480 pixels should be able to do this. Black and white system seem to show it best, its a little harder with the color screens but it will still show the echos if it is set up right.

I don't want to get into an argument if I am right or wrong on this cause it will go no where, Lowrance told me point blank, they have no idea what I am talking about, and if they could prove it, with what I am saying they would sell the unit like that, saying you can tell the difference. But one of there main people that makes there units told me, that he has never been out with that unit catfish and never has paid any attention to double echos on fish, but he did say you might be 100% right cause you will get a echo off a hard surface then a soft return. So if that's the case, would no scaled fish be a soft return and a hard scaled fish have a hard return. I think so. but its only my opinion, not Lowrance.

Thanks
D/H

[4Low]

Well, just for invigorating conversation and not to be argumenative, I'd like to give my opinion on this subject. My opinion is that there is no fish finder on the market today, nor will there ever be one that can tell the difference between scaled and non scaled fish. The physics and mechanics of ultrasound disprove this theory completely. I've been a medical ultrasound tech for many years now and have thorough knowledge in this field. The ultrasound beam transmitted from the transducer propogates through the body of all fish, scaled and unscaled at the same speed, which is 1430 m/sec. What creates the arch is the swim bladder filled with air, which sound travels much slower through, thereby creating the arch. The pencil line you are describing is the fish moving through the water. Remember that the fish finder is constantly transmitting pulses down to the bottom. When the fish is swimming and moving about or "through the cone" you will see these lines on the screen and when the "cone" of the fish finder's sound waves are directly above the swimming/moving fish, it will emit the full arch on the screen with the pencil lines behind it where it is swimming or moving from. This happens because you have a good unit with a lot of power and a high pixel count. This also explains why you are catching more catfish when you don't see the pencil line, which would be one of 2 reasons. The first of which is that you won't catch the one with the pencil line because the fish has swum away, and the second reason is that it may be a moving gar, striper, paddle fish, grass carp, silver carp, buffalo ect. that is not interested in your catfish bait. The arches without the pencil lines are fish that are "still" and are more than likely catfish (in this instance because they are on the botton in 40 ft of water) and that is why you have a better catch ratio when targeting those particular arches. Also, think about this, if the manufacturers thought there might even be the slightest chance that the units could tell the difference, don't you think they would advertise that? The market is so tight with those companies they are all looking for the "edge" over the other guys. Unfortunately for us, that will never happen because the simple physics of ultrasound will not allow it. DH, I have no doubt you are very knowledgeable with your particular unit and I respect that. It us up to us as fishermen to understand the dynamics of our equipment, become familiar with what we are using and get accustomed with the information provided. You have proven this by showing us your pictures from the previous thread. With good units it is easy to see the difference between weedbeds, mud, trees and rocks, but with today's technology we can't tell scaled from non scaled.

[Bill in SC]

Personally, I don't see why folks spend thousands on a depth/fish finding sonar. I bought an Eagle FishMark 320, ($150) and I DON'T have it set on the arches. When I find fish in structure, or anywhere else many times I pull 'em out. I have really enjoyed reading the debate though. I will agree that other than the rods and reels, boat and bait, the fish finder is THE most important tool to assure success. Heck if I hit the lotto, which I don't play, I may buy me one of them new fangled hot shot megabucks sonars! :-) I thank DH for suggesting the sonar in my price range.
Bill in SC

[4Low]

Before posting this, I wanted to add this paragraph at the beginning to make it a little easier to understand. When thinking about frequency, think about 100 hooks on a trotline. If the frequency is high, the hooks will be close together and we can see everything around them very clearly, but the line will be short. If the frequency is low, the hooks will be spaced further apart. We can't see as clearly now, but we can see further as the line becomes stretched out. We can make the line as short or as long as we want, but when we make a change to gain clairty we lose depth and to gain depth we lose clarity. OK, here's the rest.

From the previous post, "It doesn't make sense" to you because there is such a tremendous difference between the frequency of medical diagnostic ultrasound and the frequencies of fish graphs. The frequency is the amount of "pulses" sent out from the transducer. For medical, it is between 2 and 10 Mhz, or 2-10 million pulses per second. This is super fast because we are imaging shallow, around 10 cm for the heart, 2-4 cm for the carotid arteries in the neck and 4-8 inches for a fetus. Higher frequency gives better resolution, but we must give up something, which is depth. So, with these medical studies there is a difference of 8 million pulses per second between the frequencies we use for a carotid artery study vs a fetus, but the difference in depth is only inches! Now if you take a fish and place it underwater in a shallow container only inches deep, we could tell the difference between a scaled and non scaled fish by the amount of reflection at the edge of the fish's body with medical ultrasound frequencies because the pulses are so close together. A scaled fish would represent a slightly brighter edge than a non scaled fish. We would be able to look at all the organs and we would be able to visualize the swim bladder full of air, which would resemble a rather bright white reflective oval inside the body. This is all because of high frequency and shallow depth. This would be similar to looking at an unborn fetus.

Now let's talk about low frequency. To image deep below the surface we must increase the wavelength (distance between pulses) which means we lower the frequency to about 2000 Khz. See the difference??? We now go from an average of 5,000,000 pulses to 2,000 pulses to stretch out the wavelength to our desired depths as fishermen. The lower the frequency the longer the wavelength and the deeper the soundwave will go. To gain depth we must give something up which is resolution. When we lose resolution, we lose the ability to visualize clear images like we do with medical equipment, which is why the fish are identified as "arches" on our screen, or symbols if we choose that option. Once again, this is only because of the swim bladder as the soundwave slows from 1400 msec (moving through water) to 330 msec (moving through air in the swim bladder). That is a HUGE difference in speed and it is reflected back and shown on the screen. Although there is a very small difference in the speed of soundwaves through scaled and non scaled fish, because of the low frequency, the subtle change is not great enough to be identified. The axial resolution is simply not good enough at this frequency to distinguish this subtle difference through the large difference between the water and air, or swim bladder.

Yes it is true that with these units we can tell the difference between mud, rocks, vegetative and stumpy bottoms. The amount of soundwaves that make it back to the transducer and the amount of time it takes them to return tells us this information. This is that X and Y stuff we learned in school that we thought we'd never use again...time and motion. Time being how long it takes the signal to be sent and returned, and motion being the medium (water) and what's in it. A rocky bottom will scatter the soundwaves and only a few make it back to the transducer, but they make it back fast and they are strong returns. This would give us a dark solid line on the screen indicating a hard bottom. Sand and mud would not scatter the soundwaves as much, so more would make it back to the transducer but would be much slower and weaker due to absorption. A medium colored line would then appear indicating this softer bottom. Vegetation a foot off the bottom will absorb some of the soundwaves and send them back weaker...some soundwaves make it through and are absorbed by the mud and sent back through the vegetation even weaker, and we would see the grassline above the bottom on our screen. That's how that parks works.

As for pixels, they are the smallest division of a display. More pixels will yield better detailed resolution on the screen and each pixel may be represented by multiple bits which determine how many gray levels can occupy a pixel. I'm sure you've seen the term "gray scale" before. This gives us better pictures to look at on the display screen and makes it easier to tell mud, sand, grass, etc. apart from one another. It also allows us to now see thermoclines. But, a high pixel count cannot make up for things that are not seen in the first place with low frequency soundwaves, such as telling a gar from a catfish.

As we combine what we see on the screen with what we've learned from pervious experiences with our graphs and add in a little human intuition, we can make better judgements with what we are looking at. With practice and a decent unit it doesn't take long to understand the dynamics of reading fish graphs. Like anything else, we can spend as much as we ont on one. My newest graph is an Eagle 320 that I got on sale for $129. The picture is great for the price and it has a temp sensor too. I don't care about a speed sensor and I think color graphs are overrated at this time.

After typing all this my hands hurt and my pizza is ready. I'v enjoyed this thread and hope you all have too. Let's go fishin!!!!!!!!!

[redneckradtech]

I still cannot see why that a solid or reflective scaled fish would bounce the sonar back when a soft object which would be more a more stealth signal.

[4Low]

Jerry, can't explain your different colored arches at this point in time; I've never had a colored FF before; seen some in action but was not impressed with the ones I've seen. I hope to learn more about them in the future.

Daniel, the soundwaves go all the way through the fish and and come back to the transducer no matter if the fish is scaled or not.

[waynebo]

Scales or not all fish have an air bldder that they use for maintaining depth/neutral bouyancy and thats what a fish finder use to determine a fish from debris floating underwater.small fish small bladder/big fish big bladder.

[Leftenant]

An old Striper fisherman told me that the difference between the shape of the arches is that different species of fish have different shaped air bladders. He said a Striper will show up as a sharp arch while a Catfish will show up more rounded. Hope this helps.

[catcrazed]

Wow!! I wish I could have found this page a long time ago. I want the experts to tell me how in the world lowrance can be full of fish at the 50 foot water mark and some be a dark blue pencil arch and some of the fish in the screen be thick yellow arches but these arches are the same exact length!! I know this is an old thread but in the lowrance book it saids that a hard signal would show up yellow on my graph and a soft signal be blue. I figured the blue to be soft (cats) and yellow as scaled. (gar carp etc.)