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David Waters
05-13-2005, 09:10 AM
does anyone have a good definition of Thermocline? I think I am pretty sure what it is, but would like to know more about it.

VietVet68
05-13-2005, 09:25 AM
does anyone have a good definition of Thermocline? I think I am pretty sure what it is, but would like to know more about it.
<chuckle> I would love to reply to this, but this baby has MooseIam written all over it! "Pictures at 11:00"

TAE73
05-13-2005, 09:53 AM
Where the warm water meets the cold water in the vertical water column. The cooler water has less oxygen content, thus fish will hang out just above this point being cooler than the water above. Most lake have aleast one, some will develop 2 therocline, these develop mid june depending on where you live.

Bruce Carp
05-13-2005, 09:59 AM
It's where most of the fish will be found during the summer! Normally a 3-5 ft band of water as TAE has stated. It's where you catch the crappie.

whizkids
05-13-2005, 10:09 AM
Understanding how thermocline or the lack of Thermocline can effect your fishing
http://rdlwebs.com/texasfishingmagazine/september2004articlesthermo.htm


Lowrance has a tutorial on thermocline
http://www.lowrance.com/Tutorials/Sonar/sonar_tutorial_08.asp

In fisherman did an article and daily log on lake turnover:

http://www.in-fisherman.com/magazine/articles/IF2706_turnover/index.html

B n M pole company had an article where trolling crank baits over the thermocline was mentioned.
http://www.bnmpoles.com/newsletter/100404/100404.html

Thermocline discussion by Moose and others on Patoka Lake. Of intrest to all CUSA classic guys.
http://www.crappie.com/gr8vb3/showthread.php?t=1386

David Waters
05-13-2005, 10:21 AM
Holy crap. Thanks guys!!!

VietVet68
05-13-2005, 11:11 AM
Good Going Whizkid:

I have a feeling that these links are going to answer the question. I can sit back and enjoy my cup of coffee. LOL

I will say this. I took some temperature measurments this spring on the lake I fish and found a thermcline had already formed at the 10ft level back about a month ago. Back then we had some really nice weather. Calmn and sunny for almost a week before it turned very cold again. That was early April or Mid April when I found the thermocline. The lake I fish is deep and the water was over 30ft deep where I did my testing.
Awwwww.....no pics? :(

TAE73
05-13-2005, 11:21 AM
Awwwww.....no pics? :(

Here's a pic for ya Vet, we'll let moose finish his coffee.

VietVet68
05-13-2005, 11:28 AM
Here's a pic for ya Vet, we'll let moose finish his coffee.
Ewwww....now that gives me a warm & cozy feeling, thanks!

David Waters
05-13-2005, 11:43 AM
somehow, I knew this thread would be a good one.

MoSam
05-13-2005, 12:12 PM
The trick i have found to thermoclines is adjusting your depthfinder to locate the thermocline then fish about 1-3 feet above it. If you can find a long point that continues into a creek channel with a thermocline, that is a money spot!

Shaun

VietVet68
05-13-2005, 12:23 PM
OK, we are on a roll....let's take it up a level. What are your thought's on
"bottom turn-over" and/or temperature inversions?

CrappiePappy
05-13-2005, 01:09 PM
and I'll add to it ........

Any cover that intersects the thermocline is a potential hot spot. Consider the thermocline as an "edge" that right angles into the "solid" cover. Thermoclines also make the lakes they occur in, smaller (in water volume) ... as most of the water below the thermocline doesn't have enough dissolved oxygen, to sustain a fish's breathing for long. That eliminates a percentage of the water in a lake - forcing the fish to utilize the upper layers of water. When those layers get really warm, and fish cannot utilize depth for comfort & security ..... they stack up in the water column where it's always "shaded" (shaded water is cooler) - even if that water is extremely shallow. Now you know why lily pads, grass beds, blowdowns, & docks are such good places to fish.
*********************************

Temp Inversions, or "turnover" - occurs when the heavier, colder surface water drops thru the level of warmer water below it. This can happen in Spring & Fall - when the weather changes are more pronounced. This can mess up the fishing, at times, due to the fact that it can "foul" the water with bottom debris/matter or simply neutralize the seperation of the water levels and allow the layers to mix (providing a broader volume of oxygenated water)....which will allow the fish to scatter thru a wider range of depths. It doesn't "always" happen, and it doesn't happen on all bodies of water. And, luckily, it doesn't usually last very long. ......... cp :cool:

whizkids
05-13-2005, 03:22 PM
[
Temp Inversions, or "turnover" - occurs when the heavier, colder surface water drops thru the level of warmer water below it. This can happen in Spring & Fall - when the weather changes are more pronounced. This can mess up the fishing, at times, due to the fact that it can "foul" the water with bottom debris/matter or simply neutralize the seperation of the water levels and allow the layers to mix (providing a broader volume of oxygenated water)....which will allow the fish to scatter thru a wider range of depths. It doesn't "always" happen, and it doesn't happen on all bodies of water. And, luckily, it doesn't usually last very long. ......... cp :cool:[/QUOTE]--------------------------------------------------------------------------------- All true and it can ( not every time) have major kills of {Threadfin Shad: Although the thredfin is probably not native to most reservoirs, it has been widely introduced into them as a forage species. Threadfin shad feed on plankton and range in size from 1 to 6 inches. Threadfin shad are sensitive to cool temperatures, and decrease swimming and schooling abilities at temperatures of 45 deg. and below. }

Barnacle Bill
05-13-2005, 03:55 PM
Good info here. Whats it called when there is a layer of very, very muddy water say about a foot down? Is that just mud accumulating in the thermocline?

VietVet68
05-13-2005, 04:08 PM
I think CP and Whiz did very well. The only thing I might add is I have heard one of the theories about "turn-over" to be......

Especially in strip pits, as the decaying matter on the bottom produces gases, the bubbles of gas are trapped under the mats of vegetation until they produce enough boyancy to float the mat loose of the bottom. When that happens it also releases a ton of both silt and micro organisims, thus clouding the water and letting the bait fish feed anywhere they wish, thus letting the game fish feed furiously for the first several hours. Fact or fiction?

whizkids
05-13-2005, 04:31 PM
Good info here. Whats it called when there is a layer of very, very muddy water say about a foot down? Is that just mud accumulating in the thermocline?------------------------------------------------------------------------------------------------------------------------------------------- I wonder if there is a way to identify that. In Power generation reservoirs especially of the size we have, it is not unusual for muddy water to be coming in as fresh muddy water and going through the majority of the lake under the surface and coming out at the generator muddy.This is especially true when there ar localized heavy showers. A significant portion of the lake will remain clear on the surface with muddy water under. I know of no way to identify at what depth the muddy water may be.

whizkids
05-13-2005, 04:33 PM
I think CP and Whiz did very well. The only thing I might add is I have heard one of the theories about "turn-over" to be......

Especially in strip pits, as the decaying matter on the bottom produces gases, the bubbles of gas are trapped under the mats of vegetation until they produce enough boyancy to float the mat loose of the bottom. When that happens it also releases a ton of both silt and micro organisims, thus clouding the water and letting the bait fish feed anywhere they wish, thus letting the game fish feed furiously for the first several hours. Fact or fiction?----------------------------------------------------------------------------------------------------- First couple of hours may be the key phrase.I don't know about pits, but if that happens on Lake Rhodhiss , as it does in the fall, it is a good time to go elsewhere.

hawkman
05-15-2005, 08:38 AM
I have been wondering about this for a long time & now looks like a good time to ask. Would a power supply reservoir like High Rock Lake (approx. 15,700 acres) have a well defined thermocline? It seems that the constant in-flow of The Yadkin River & several major creeks, along with pulling of water through the generators, would keep the water stirred up. Opinions please. I haven't read the articles in the links yet, they might answer this.

whizkids
05-15-2005, 08:54 AM
I have been wondering about this for a long time & now looks like a good time to ask. Would a power supply reservoir like High Rock Lake (approx. 15,700 acres) have a well defined thermocline? It seems that the constant in-flow of The Yadkin River & several major creeks, along with pulling of water through the generators, would keep the water stirred up. Opinions please. I haven't read the articles in the links yet, they might answer this.------------------------------------------------------------------------------------------------ I believe High Rock would have a thermocline in the waters near the dam. The turbines pull from the bottom, keeping the warmer water near the surface. It may vary from year to year with rainfall but I feel certain that the deeper areas of High Rock will stratify.