As I've read PB over the years, one thing pounded into my thick skull is that fish have strong temperature preferences. Rainbow trout die when temps exceed the low 70s. LMB prefer 65 to 83F, though perhaps Fla LMB like it a bit warmer. And so on.

Indeed, Pondmeister Lusk wrote an article about why BG can grow as large, or even larger, up north than down south: There are just as many "perfect" BG temperature days in Yankee land as Dixie.

LMB during hot summer temps stay in the therocline, despite low O2 levels, to keep cool.

Okay, so we know that fish growth is limited by temperatures. Too cold, they stop feeding. Too hot, they stop feeding (or at least slow down drastically).

But instead of just taking this as a given -- down here in the south, bass won't grow much for perhaps a couple of summer months -- why not try to do something about it?

I got to thinking about this when I last walked out on my dock. Fish everywhere, of course. Feeder & structure, so why not? But the water is warming fast, so...

Then I realized that the water isn't warming so fast under the dock (and under the pontoon boat attached to the dock)

Dock fishing during the summer is very effective. But what if it's not just about structure, nor about shade for their eyes, but lower temperatures? I recall reading an article about False River, a large oxbow lake near Baton Rouge, where measured temps under docks during summer were 20F lower than surrounding water!

So would it make sense on a pond to use floating white plastic or wood to block the sun? Note that it would also knock down unwanted weeds, as well as cooling the lake, especially in that area.

there are limits, of course. Such a structure would block air mixing with the water, which could be a problem depending. Spawning beds need sunlight, too! But maybe we should be thinking harder about managing sunlight & heat, rather than just accepting the summer doldrums.

Before you dismiss me as crazy, recall many folks have small ponds where a shaded refuge area, say 10 by 20 feet, would make a difference. Or like my own little forage pond, all 1/8 acre of it.

White, water resistant tarps are not expensive. And, even in a large pond, they could be useful by shading certain areas where you wish to inhibit weeds, birds and maybe attract fish.

Okay, that's all I have to say on a subject that nobody wants to discuss. Talk with me after the summer, I'm gonna try this out at least on a small scale.

I've brought that tarp idea up before to knock down weeds - it'd work great to cool some water as well! Good point on the docks

The floating islands and planters discussed in other threads, if large enough, would block some sunlight as well

My pond has a spring fed creek that empties cool water into it - I know for a fact this cools the pond when flows are high (like the string of 90's we've had - my creek outflows are much cooler than surface temp in the pond). My walleye are loving that cool water near the creek mouth

My pond also sits in a deep ravine with plenty of shade. It holds well in the late winter

Let us know how it works out anthropic.

Or you could just do what I did with my sediment pond. Let the FA get out of control and the floating mats provide shade.

I did notice tonight as I fed around my main pond (which has a small amount of FA mats just around the edge) the CC could come right from under the FA mats is less than a foot of water out to get their supper. I figured they were feeding under the FA but they may have been using the shade. Mid 90's here today. That is darn hot for the first of June for us.

It looks like my older pond is clearing and will become mostly covered with FA, maybe until late fall, depending on rainfall. Then again, maybe the FA will use up remaining nutrients and become self limiting. I guess FA does provide shade and is not harmful to the fish.

Anthropic,
My thought on temp control was to bring up some of my very cool water from the deep end during the summer and see if it cool the surface. Same goal, different approach. I' try to get a test run this summer and see what I find.

Good idea, Brian. From what I've read, you might want to do this at night, otherwise there'd be no thermal refuge during the heat of the day.

Interesting comments about FA. They do provide shelter for prey, cover from predators, and shade, all which may attract LMB.

But I'm not sure that FA or other emergent/floating plants actually cool the water. Water hyacinths, for example, make the pond hotter, as the plants retain more sunlight than does the water. That's one reason why I thought a white tarp might offer better cooling.

I'm even thinking now about using 8 foot garden stakes to place vertical structure, then fasten the tarp to the garden stakes. Shade plus cover! Only drawback is that it would be tough to fish, though maybe this is actually more of a plus.

It may be to early in the summer to tell right now, but my water temps seam to running a little cooler than the hot days last year. I am running the diffusers at night only this year or 9 to 9:30. My pond will not be near as deep as Brians and I would think the deeper water would be cooler than mine at 12' depths.
and Frank, if you try out the stakes with blue or white tarps then the lmb should come out of the shade when a bait is thrown at the edge or side of the cover. I would think if u set the tarps a foot or two above the water the wind movement might help to cool. I think it can work but might take a bunch of tarps to see measurable decrease in temps.

Well, they do make tarps for football fields, but that costs serious money! Besides, I expect it wouldn't be practical.

I'm still pondering on how best to approach it. If tarp set much above water, I fear next windstorm will either blow it away or rip it to shreds. Maybe it will have to be able to adjust to water level. Hmmm.

Grab up an ag round bail tarp in silver.

I run our aeration at night after the water reaches 60F. Keeps our perch feeding all summer.

Cheers Don.

I suppose you could also plant some trees somewhere to break up the harshest sun at the peak heating part of the day. Of course not on the dam, and far enough away as to not have roots in the pond. This means a quick one-year experiment is likely not possible. Lombardy Populars are fast growing wind/sun breakers, but don't do well after 20 years.

Good idea, Don. I've wanted to aerate for several years, but plan went sideways when utility said it would cost an extra 3 or 4,000 just to set up wiring!

anthropic, this thread is taking off!!! Thanks for starting it. And for prodding us into thinking of something nearly "out there".

I've waded into the FA mats in our pond and felt the much warmer water right in the mats. Something's going on there. The FA may be leading to solar gain; the mats may be preventing water mixing. Any shade the FA is providing may be canceled out by the apparent heat gain.

I like the tarp idea. Can you suspend it from floating supports? Can it be rigged in a manner that allows it to be lowered to the water surface to survive a wind storm, then returned to suspension after the wind is gone? Just thinking aloud.

I've contemplated black tarps to warm my pond, as the incoming water is from a trout stream, and I'd like my bass and sunfish to do better than they do. Tilapia are not feasible at this time.

4corners, thanks for the encouraging words. You've even have taken this in a direction I've never considered, black tarp to keep water warmer. Here in Texas we usually have the opposite problem!

Wonder if placement of black tarp would help keep ice off a particular area? Or maybe placing black tarp on ice would cause it to melt?

What I might try is to set up stakes with similar brush & artificial structure around a couple of similar areas. One area would be open, the other covered with a white or silver tarp. Then could measure water temps under the tarp compared to other area, maybe make observations through fish eye camera and fishing. Could be fun!

Maybe it will be a fiasco. But there was a time when the idea of stocking 30 BG to 1 LMB seemed ridiculous, and a time when actually feeding BG and even trained LMB seemed absurd, and when stocking HSB in ponds seemed crazy. As you say, who knows where this might lead?

PS Saw another Bob Lusk facebook video last night, and was interested in his comment that pond needs 20 to 30% good habitat to maximize the fishery. I wonder if relatively cool, shaded water in summer might be considered "habitat?"

Don, where would I find this? Is it waterproof?

A couple of years ago I saw an add on Craigslist, where someone was selling surplus 4'x8'x2” Styrofoam panels for $10 apiece.

If a similar deal could be found on some damaged insulated steel building panels, they would be ideal for providing a floating shade, as the steel skin would be much more durable.

https://www.tscstores.com/Bale-Tarps-C725.aspx

I have always got them from TSC.

anthropic, yes, relatively cooler, shaded water can be considered higher quality "habitat" if that is desirable to the particular species living there.

I'm considering placing some kind of porous cloth, such as landscaping fabric, on the surface of my pond this fall and winter. We'll see if that helps keep an area ice free and even warmer. I'll use something porous so that if that is the only ice-free spot on the pond, there will be potentially some oxygen and other gaseous exchange.

We live back in on a gravel road. Each winter after a few several inches of snow falls, I may use 4 wheel drive to get out our driveway and out the gravel road to the blacktop highway. On a sunny day, I'm often amazed that the paved road will be completely free of snow and may even be drying off, whereas the gravel still has inches of snow on it. Our darkly colored cars will be snow free long before the melting starts on my white truck.

I have seen people attach tarps to pvc frames attached to floating barrels for summer shade. Same concept could be used with Styrofoam panels. Most fish love extra shade in med to deep water during summer heat.

Anthropic, very interested in how this goes for you as I would like to find a way to keep mine cooler as well. My pond is just under 1 acre and the surface temps, as of right now, are running in the low 90's! It fact, it was 83 degrees two few down! Something you may want to look into is Craig's List. There is a continuous ad that I see around here where someone is selling vinyl billboard coverings for only $10 each. If you could get some mostly white or light colored ones, that would be a cheap way to try it out. Just a thought...

Good idea! I'll have to check it out.

My oldest fishing buddy is going to drop by next week so I'll have some help setting up some habitat, including tarp (I hope).

We always talk about water clarity as part of having a healthy pond, being that trying to maintain that magic 18" or so as a basic indicator of pond health. I can tell you, and I don't know if much thought has been given to this, but BOWs that stay somewhat stained tend to keep relatively warmer temps. The sediments suspended in the water column act as conductors for heat transfer, much like riprap on a shore line will remain warmer in winter than those banks without it.

Case in point...Tellico and Fort Loudon Lakes in East Tenn are right next to one another and share the same dam, connected by a short canal just above the dam. Fort Loudon is always stained and warmer than Tellico which can have visibility over 5-6 feet and will be 10-15 degrees cooler at the canal side on any given summer day.

Just some more food for thought.

Excellent point, Mike. Another reason why it's best to have lower fertility in summer than spring, I guess.

By the way, I ordered 20'x36' tarp today. They were surprised to hear about my proposed use, but thought it was worth a shot. Should arrive next week!

Frank, is that a bill board tarp? If so please give out a report on condition if you don't mind.

Thanks

Is that tarp white or did you go with the standard blue? I know the white will reflect more heat up and away from anything below it. The blue ones I've used, even set high off the ground still get pretty warm underneath, but in this regard, merely providing shade either would probably work great. Really interested in seeing how this works out. Please keep us updated.

Tracy, I decided to go with higher quality stuff for my first try. Supposed to be waterproof, sunlight resistant, tear resistant. Designed to keep hay cool, silver color.

I have no idea if it will work out, but will keep you in the loop. Probably will need to put some Styrofoam under it in spots so it doesn't collect rainwater or get waterlogged.

Mike, thanks for the encouraging words. I'll try to post some pics when it arrives & is deployed. I'd worry about cutting off interaction between water & air if it were too large, but doubt this will be an issue given relatively small size.

Its called the black matter effect. In the winter it will effect even posts in the snow. Post heats up and will radiate heat melting the snow close to the post.

I got my silver tarp! Can't wait to deploy it. Originally I was thinking about putting it parallel to a main lake shoreline, but now am considering a shallow back bay that is filling up with chara. Maybe the shade will slow or stop this process, as well as cooling a hot area.