Fish symbols or arches?

I've noticed that quite a few members here still use fish symbols rather than learning to interpret arches. I've been wondering why. Did you know that when a fish symbol shows a fish at 15' for example, that does not necessarily mean the fish is 15' below your boat but rather 15' from your transducer. It could be holding 8' deep but off to the side. Numerous times the fish finder will be fooled and display a fish symbol when all that is really there is debris. You will only see a solid looking arch if you passed directly over the fish, otherwise you will have a partial arch telling you that the fish is off to the side. If your boat is dead in the water fish will show as lines. If I don't see an arch (or partial arch) I know that it is something other than a fish. So do tell, why use fish symbols? :confused:

never knew what the difference was i thought they meant the same thing. i guess i should start reading the directions. But with a FF thats costs <$100 i mostly use it for depth anyway. thanks for the info.:)

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Originally Posted by Crappisaurusrex

never knew what the difference was i thought they meant the same thing. i guess i should start reading the directions. But with a FF thats costs <$100 i mostly use it for depth anyway. thanks for the info.:)

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thats my thoery, Tap you sure know your electronics, ive read my manual to my eagle FF but doesnt elaborate much. I really dont know much about reading them so i didnt put much money into it. Id definately consider upgrading if i could learn more about reading them.

I look for arches. If You set the graph up right with the right sensitivity and can read arches, they will eliminate a lot of water. This really comes in handy in the winter. You can find productive water pretty quick that way.CF

Whenever I get a new finder I turn off those stupid fish symbols. Anything that returns a signal will show as a fish. Whether it be a water logged leaf or an old beer can.

I keep my symbols off, although I rarely mark anything. Structure is ALL I ever see unless I'm in 20+ FOW, then and only then will I see a fish arch. I had never seen so many fish arches until the time I went with Tap to Buggs Island. That doesnt happen in SUffolk, atleast not with my depth finder.

And when I set up my Lowrance with the transducer on the trolling motor I remember there was a setting for how deep the transducer was in the water so it would compensate and read the actual depth of the water and the depth of the arches, not how far from the transducer the objects or the bottom was.

I have the fish symbols turned on, mainly cause I am blind as a bat while wearing sunglasses. The polarizing sunglases do reduce the visibility greatly and with the symbols on I can read the depth easier. The arches are all still there, so it is just an addition to what you are seeing. The computer determines weather or not to put a symbol on the screen based on the arch signal. So if it is a arch you are looking at you are making the determination. whats the differance? You still need to believe in your machine.

At BM when I go over a tree that is 5feet under the water I may get an arch and a fish symbol. I know it is a tree because the SI shows it. But it may also have a fish hovering over it. On most drops I see 3 or more arches. I know fish hang on a channel edge and the fish finder proves it. I saw many fish hanging at 23feet, could not hook one to save my life, but when I dropped a worm down to 23' bam! hooked up channel catfish. So now I know what is at 23'., cats.

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Originally Posted by Flatwater

The computer determines weather or not to put a symbol on the screen based on the arch signal. So if it is a arch you are looking at you are making the determination. whats the differance?

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My experience has been that you will see fish symbols where there are no fish. Does your unit put a fish symbol on a partial arch? If so, it will give you incorrect depth.

Here's a great link with lots of info. And here's a quote from it.

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Advanced Fish Symbol I.D. is designed to give a simplified, easy to interpret display of suspended targets that are assumed to be fish. After gaining experience with your sonar, you will probably turn it off much of the time so you can see all of the detailed information on fish movement, thermoclines, schools of baitfish, weed beds, bottom structure, etc.

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Here's a school of baitfish but if I had been using symbols I would never of known it.

http://img.villagephotos.com/p/2004-...day018copy.gif

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Originally Posted by crappiefarmer

I look for arches. If You set the graph up right with the right sensitivity and can read arches, they will eliminate a lot of water. This really comes in handy in the winter. You can find productive water pretty quick that way.CF

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And if you dont see arches, atleast maybe you can find the bait....which draws the "arches".;) I got off the fish symbols as soon as I got my first depthfinder, which was an Easgle 480. Mow I have a Lowrance LMS 522igps with a lake maps chip which is about as big a step up as going from a word processor to a PC computer. Now I feel I just got in the game when I upgraded to the Lowrance (a year or so ago). I can only envy the guys with those big 10" screens with side imaging.:rolleyes: There's just so much more you can learn and see with those higher priced units.:rolleyes::o

hey tap my unit shows bait balls and fish symbol. i have a dual beam and when my unit marks fish it tells me when the fish are under the boat or off to the side. and when i mark a school of fish i then swing the boat to bring my baits over them. i never did have much faith in lowrance with the fish symbols on. it marked stumps and logs as fish. i have total confidence in my humming bird unit. when i was running back on b/m i marked three schools of fish on points about 8 ft deep. and i know they were specks. also on northwest in the winter with my unit i can run at 1/2 speed and look for fish om the creek channel . jim

http://i299.photobucket.com/albums/m...55/BMSI017.png
This is a tree laying from shore to the water at Burnt mills, on right upper side, you can clearly see the tree limbs. on the top fish finder screen you see the fish symbols and arches. I cast to the end of the tree and caught 3 crappie, all right at 10". I see both the arch and symbol, while out in the boat in the wind and sun I see the symbols clearer and most important is the depth. Cast 1/32 head jig and count to 6 and retreive slow stopping a lot. I use ez bendable hooks so when you catch the tree you can bend it free.,
Now with the push of one button I get this screen.
http://i299.photobucket.com/albums/m...55/BMSI018.png
bottom right just over the 6 is the tree, only now at home you can see the fish, they are the white spots, over the 6 at the end of the tree. Out on the lake they are very hard to see on a 5" screen.
http://i299.photobucket.com/albums/m...55/BMSI009.png
this is just a random shot of screen showing archs and symbols. I clearly see both at home but again while out on the lake while glancing at the fish finder the archs are not easy to determine the depth of the fish, to me the symbol is very clear with the correct depth.

http://i299.photobucket.com/albums/m...55/BMSI014.png
I like this shot, it is an old road? or flat hill? anyway mid screen above the 3 in 83 you can see a group of fish right over the drop. I trolled this hill catching 1 or 2 fish at every pass. This is in front of the house where the big brown pine tree is laying, between the first and second lake at BM.