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What is that on my fish finder?


TyeeTanic

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Okay, I have seen two strange things on my fish finder - does anyone know what these might be??

1) A long thick line - around the 20 to 30 foot depth, and is around 10 feet thick, running for a long stretch, about 1 to 1.5 screen lengths, probably 100 feet long. Is this the thermocline or a fish swimming under my boat?

2) A very straight diagonal arrangement of dots - starting high then going lower as you move from left to right across the screen. It is extremely straight, just on a diaganal.

Thanks,

Mark

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1st thing sounds like either thomocline or a fish swimming along under the boat. It also could be a school of bait. Second thing sounds like interferance from someone else's fish finder. Were there any other boats passing by you at the time? If so, it should have gone away as soon as they passed.

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I have a Lowrance Elite 5 Gold. It is a decent unit.

I was thinking the first one might be a school of bait, but it would have been incredibly long (several hundred feet) and it was almost too uniform stay + or - 5 feet on the top line and bottom line.

Second one I never fish close to any one else but have to admit I never actually paid attention to seenif anyone else could have been close by.

Next time I will take pics with my phone and post.

[ Post made via BlackBerry ] BlackBerry.png

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Yes my motor was running. However the diagonal line has only showed up twice in several hours of fishing..

the rate of those lines will change with rpms...If it doesn't bother you, don't worry about it...if it does, try separating the ff wires, including transducer wire away from the rest of the boats wiring. Keep ducer wire separate from all other wiring. Make sure the ff is wired directly to the battery, not your fusebox or spiced in somewhere. :yes:

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It doesn't bother me - the diagonal lines have only happened twice in 30 hours of trolling.

The other image - the 30 foot deep, 150 foot long mass is interested - again not important - but if it is a huge bait ball - it would be worth marking and circling over several passes. If it is only plankton then I should just move on.

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  • 3 weeks later...

Okay, here are pics of the formations on my fishfinder.

First up are the diagonal lines across my screen - it does not happen often maybe once every 6 hours and lasts for 1 minute. Is this interference from something - if so, why does it not happen all the time?

gps_1.jpg

Second up is the 10 to 15 foot thick band that stretches over 200 feet - you will notice a few predator fish above and below this. Is this bait or thermocline??

gps_2.jpg

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1st looks like interference. (maybe from GPS or satellite signal) 2nd looks like a split screen and that frequency is picking up your dipsey. Most probable that a cross current has pushed that dipsey and some wire into the edge of the cone. Next time you see it, make a turn, speed up, put it in neutral or pop it loose & see if it moves. (watch out if you pop it loose - a fish may grab it)

Bait generally looks like a cloud or an "Ink blot."

Tom B.

(LongLine)

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I don't think it is the dipsey, the lines are set out 200 feet on my wire rods, it would be almost impossible for the dipsey to get into my radar's view without significant slack on the line.

I know that bait balls generally look like balls - but this is definitely something - you will see that even the predator fish underneath are picked up weaker than the ones on time.

It's either bait spread out at one level, or someone else said it could be plankton.

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That band is not 10-15 foot thick - it only looks to be about 5-7 ft. thick. That is a thermocline where plankton, debris, etc. is changing the density of the water near the top and where it's easier for your sonar to pick up. When the surface temp is 75 degrees and down 20 feet it's 60 degrees, there is going to be a layer of debris at that interface.

Do yourself a favor, drop a temp probe to to the same depth and see if the temp changes.

- Chris

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