Fishfinder Oddity

[OutdoorDan]

Hi all,

 

A weird thing has keeps happening to me at night - my fishfinder lights up and goes crazy. Here's a picture of what the screen looks like at night:

 

 

 

This would be everywhere - 40 FOW, 80 FOW, whatever. Going over identical areas during the day would mark the odd fish but the screen wouldn't light up like that. I don't think this is fish, so what gives? This was in the Severn Sound area, however I experienced similar things staying out past sunset on Lake Joe in the winter where the sonar would start to have weak signals showing sporadically throughout the water column.

 

Thoughts?

[mike rousseau]

if its only hapening at night and your not seeing the same thing in the daylight... i would say its fish or bait rising off the bottom to suspend....

 

but if your seeing this everywhere... then thats weird...

 

 

i see images exactly like this on my humminbird... but im catching the suspended walleye when in seeing it... the walleye rise off the bottom in the evening/night...

[OutdoorDan]

I was thinking it was bait as well but then this would go on for miles (!) of water and it's just so unlikely that there is so much bait hiding and invisible during the day. Also this shows up in 80FOW as well so I think that would discount a lot of fish rising up off the bottom. It has to be something though - all the setting and location are the same as during the day. My dad's theory is that this is some plankton bunching up during the night, but that seems a little farfetched for my liking.

[Fisherman]

I'm pretty sure your Dads theory is correct. I've experienced the same in G Bay in anywhere from 50+ feet deep to well over 100. As soon as the day breaks, it's gone. Quite a while back someone wrote an article on that phenomenon, said it was zoo plankton.

[mike rousseau]

Neat

[Handlebarz]

I know on Cameron lake I see this also but I know its bait fish and there are musky mixed in as we have caught them with our lures cursing through the school of bait. It happens at night fall I go to these spots and watch them come up off the bottom its like clock work 10-20 min before dark there is nothing then all of a sudden starting in 35FOW they start to appear this will go on until the screen is covered from 18FOW to the bottom at 35FOW. I keep forgetting to bring my under water camera to see what kind of fish are there other then musky

[OutdoorDan]

Fisherman,

 

Do you remember where that article was published? I'm really curious about what this stuff is and what it looks like. And where do they go/hide during the day -- the biomass needed to light up the screen like that over miles of water is huge.

 

Mike,

 

This looks exactly like you described - not too much going on at the very top of the water column and below about 18FOW consistently lit up. But it doesn't show up like a school of bait, rather uniformly spread out everywhere. Maybe the musky got mixed in there by chance?

[Pigeontroller]

Night time = fish activity

[Fisherman]

Lota lota, oh boy, I've run out of hair for this week already, it might have been on this site about 2-3 years ago, or possibly Spoonpullers.com

 

Pigeontroller, I won't disagree depending on the body of water, however you don't get that kind of coverage shown on his F/F, similar to what I've seen on mine in deep water for extended distances.

 

Not sure, but I think the guy that wrote the article was Vanselena, he was into designing/building transducers. Haven't heard from him in quite a while.

Edited October 10, 2011 by Fisherman

[Mike the Pike]

Just drop a jig down with minnows and bring them up.

[mike rousseau]

Well it sure isn't the fishfinder malfunctioning...

 

Or this would happen in daylight...

 

If its not fish(wich I think it is) maybe it's nessy... Lol

[adempsey]

It's probably a combination of all those things. Insect larva rise from the lake mud bottoms to feed on zooplankton at night. Smaller fish eat the larva. Bigger fish come to eat the smaller fish. You come to catch the biggest fish. Cycle complete