Sonar question

[getlinewet]

Folks, just about 2 months ago I installed a Humminbird Helix 9 on my boat. I keyed in all the suggested settings and everything seemed to look OK. Then about a month ago, I noticed everything below about 15-20 feet looked like it was crowded with material of unknown origin.

I'm on the Blackwater and this condition seemed to exist from B35 almost all the way down to Gills Creek where the condition disappeared. Reducing the sensitivity has eliminated most of the problem, but my question is, was what I was looking at the thermocline? What else besides tremendous pollen and silt could cause this?

Thans in advance for any assistance.

[31Airborne]

sounds about right for a thermocline. the thermoclines we see in lakes during the summer are well defined and often have tons of stuff cluttered around it. the densities of the water layers above and below are dramatic. the signal often resembles a band of clutter - tightly packed icons of all sizes kinda stacked inside the band.

only thing that would keep me from being more definitive is the location - a river, and one that's experienced a lot of flow recently. with the recent warm temps during the day there is no doubt some temperature stratification going on in the water. there's also a lot of stuff still hung up in or coming down the rivers. since we've been relatively rain-free the past few days I wonder if what you saw might be a band of trash/silt settling.

if the signal you're talking about is uniform and perfectly parallel to the bottom it's probably a thermocline signal. if it's irregular and varies in depth it may be settling flotsam.

[johnr]

Cold, muddy, trash water under a layer of warmer water. See it sometimes after a big storm in late summer early fall.

[stripersniper73]

That was a mud line I seen it not thinking when I pumped water for bait tank looked like chocolate syrup

[greywalls]

That's pretty wild that the water will stratify like that, whether based on temp or sediment. Interesting stuff.

[31Airborne]

The water has always done this, greywalls. It's only recently - with the advent of modern sonar technology - that we've been able to see it so clearly, distinctly. So much to learn, so few days on the weekend. I need to retire . . .