I put this here rather than in the aeration section because I think that aeration is only part of the solution.

Here's the scenario:

Northern Pond. Windmill aeration system, no supplemental feeding going on. No underwater plants to speak of in the pond.

A fellow PB'er had a 1 ac groundwater pond dug in 2008. The pond was dug in a wet spot in a mature woods, with trees 40'-60' tall surrounding the pond on all sides. There is a 75'-100' perimeter grassy area around the pond before the trees start.

It's water level has flowed and ebbed with the groundwater level, due to the sandy soil - no clay available to line the pond. The pond was spec'd. out at 12' deep in the deepest area, and the contractor made the sides roughly 2:1. Right now the pond is sitting at .72 ac, measured with handheld GPS with area calculation turned on. Currently, with this water level, the pond has the deepest part at 8'. If asked what the water depth was right now, I'd say 50% of the pond is 0-4' deep, 30% 4'-7' and the last 20% between 7'-8'. I don't know if the pond was ever full other than one time for a few months. If I were to guess, the pond will stay at roughly this level, maybe a foot deeper, but up to 2', maybe 3' shallower during dry periods like late 2010 to early 2011.

The pond was stocked light. First with FHM/GSH then later on with 125 RES that are now 5"-6" and a couple hundred YP that are now 4"-7". This pond stocking plan was to have SMB/RES/YP along with FHM/GSH for forage when stocking was completed. Fyke net survey last year showed no recruitment from either the RES, YP, GSH or FHM, but there was GSF recruitment. GSF weren't known to be in the pond until the Spring of 2011, but in retrospect they most likely were there when the pond was dug in the first place. (seasonal wet area in the woods)

Last winter, the O2 levels were monitored, and it showed a low of 5.9 mg/L with the windmill diffusers turned off. Last winter saw more ice and snow cover than this winter by far.

This winter the O2 levels were not monitored, but the windmill diffuser was turned on. The RES/YP/GSF and forage fish were in the pond last winter.

This October, 100 10" HSB and 20 2# RBT were stocked. The HSB to reduce the GSF population, the trout for the table. The plan was to remove the majority of HSB before stocking SMB.

The ice has been very thin, and virtually no snow cover. All was good until yesterday when a bunch of HSB were found dead. We have had a relatively calm, overcast period the past few weeks. The pond is ice free right now for about 20%-30% of the surface area, and has had a minimum of 10% of the surface area ice free all winter. No fish were noticed piping at the surface, but the pond owner does not live on site.

I counted 49 dead HSB and 1 dead RBT (laying on the bottom) today. I saw FHM and at least one large fish chasing them in the open water today.

The current plan is to drop the water level when temps rise, remove any good fish and relocate them to another pond on the property, then kill the remaining fish with Rotenone, drain it even further and hit it again with Hydrated Lime to ensure all the GSF are eradicated.

There is electric near the pond, and there are plans for a Koender EL2 compressor with a membrane type diffuser to be used in conjunction with the windmill.

What should be done to ensure that this doesn't happen in the future when the SMB/RES/YP/GSH are restocked?

What stocking rates for those fish should be used in this pond?

I think the biomass is pretty light for this sized pond. Going by what was caught in 3 or 4 different weekends of sampling with a fyke net, each 24 hr period showed 40-60 GSF caught, mostly 2"-4" in length. I'm estimating on there being less than 300# (probably closer to 200#) of fish biomass in the pond at the time of the Winterkill.

I think it happened due to (1) warmer temperatures - warmer water holds less oxygen and oxygen is consumed at a higher rate by organisms, (2)several days of cloudy weather - no sunlight, no photosynthesis, no oxygen production, and (3)no wind - no windmill aeration and no surface disturbance or diffusion of oxygen at the surface. The only thing that could prevent this from happening again is a reliable electric air compressor.

Would you mind take the last reading of O2 concentration in the water before the transfer and eradication process? O2 may not the primary suspect.

HSB have high DO needs, especially when larger. Sorry to hear they died on you. I suspect your other fish besides the trout are probably fine.

Leo, that shouldn't be a problem. Sue, I doubt water temp came into play, there is still ice on the pond. Temp shouldn't have changed even one degree. Cj, I don't think all the HSB bit the dust. I saw a swirl in the pond that could only be made by a fish around 10"-12" long. I doubt any of the HSB that kicked the bucket are larger than that. They were stocked the first week of November as 10" fish.

Scott

Why does client want to rotenone the lake? GSF will not likely pose a long term problem with YP, SMB, and HSB hammering them...just wondering why he's so set and starting all over? Not like he has a BH or White Perch infestation....then again, since you are applying the rotenone service maybe I have my answer already! The client is always right!

Is there a chance that groundwater flow through the pond brought on low O2 from the ground water? Since it is capped with ice, perhaps this flow-through removed a good chunk of the O2 and it couldn't be replenished.

Just a guess.

Scott,

Let me know if you want to use my D.O. meter although I'm not sure how you'd be able to get a safe reading with the half arse ice conditions we are having.

Have you had the water tested ? My guess is its not primarily an O2 problem. Did only HSB and a few trout die?

HSB are not particularly susceptible to having O2 problems in cool water.

One thing to note ,which may not be applicable in this case due to aeration, are the studies that indicate that waters which winter kill tend to be repeat offenders over time.

What changes occured over the last mth ? Aeration started , large run off , land fertilized , anything put in the pond , plants die , for example ? Did you look at the dead fish closely? Has /was there a plankton bloom in the past ?

liquidsquid, that is a very good possibility due to the porosity of the soil and the way that the pond is constructed. The pond is built so that ir receives absolutely no runoff from the surrounding land. All water that enters the pond has to come from underground or direct precipitation. The level of the pond has increased about 18" to 24" from October.

Thanks Cecil. I can drop my boat in the open area, or take a sample while in chest waders.

Eric, the HSB and RBT are the largest fish in the pond, and the only predators besides GSF. I'm assuming all the trout died, but I cannot be sure how many of them died unless they float. Only HSB and RBT were observed dead.

Changes in the last month was a warming trend that melted any snowpack that there was, and a melting of the ice. Last week there were a couple of days where the heavy fog didn't burn off until 1:00 p.m. and little to no wind. It's been overcast for a considerable amount of the time during the past few weeks with little wind. Aeration starts/stops with the wind. Diffuser is in 3' to 4' of water, and gets turned off for the summer. Diffusers are placed both deep and shallow in the pond and are switched for summer/winter use. Two of the dead HSB had 1" or so "hairs" growing all over them, but all the rest of the fish that I could closely examine were fresh dead - still had the stripes and their colors. Visibility in the pond has stayed around 36" or so from looking into the water from the bank and is a brownish, not greenish tint. There are oak leaves that blow into the pond during the Fall due to the pond location, but that cannot be changed. In the Fall, when the grass is cut, all the leaves are blown into the woods.

No, the water has not been tested. Would shipping a sample to TAMU frum South Bend, Indina make it in time for the test results to be valid?

There are 2 other ponds in close proximity to this one, within 300 or so yards. Pond #2 is stocked with the the same fish, minus the GSF, HSB and RBT. Pond #3 has BG, PS, FHM, GSH. All stocked lightly, and none of those shows any signs of winterkill. Those ponds are constructed exactly the same as this one and are groundwater ponds as well, but those ponds have electric compressors running the diffusers along with windmill diffusers in pond #2.

Were all the dead fish species sourced from the same place ?

I would suggest you get a water test like those done for a water well. I bet you have a local/state level test source like TAMU also.

Scott,


O.K. here are all the even remotely possibly causes and my comments. Sometimes mortality is caused by a combination of factors but typically hypoxia is the highest probability.

1.) Ground water influx zip in D.O. and the already low water volume (4 feet?) caused a hypoxic condition due to the shear volume of the ground water influx.

Comment: It would have to be a significant influx of low D.O. water this time of year as this cold of water typically has lots of D.O.

2) A lot of snow blew and drifted over the ice you didn't see and had melted by the time you came out? That combined with low water levels could have been a factor.

3.) The fish were caught and released in cold water prior to ice cover by your client or someone trespassed and did so. Having recently been stocked the fish perhaps were already in a stressed condition. Some fish have problems with catch and release in cold water and develop water fungus problems.

4.) The fish went into the pond in less them optimum condition. Or the water chemistry is so different from what they are used to this along with other factors put them over the edge.

5.) The low volume water was subjected to a rapid temp change (dropped in temp quickly) along with a heavy snow fall in open water. We did have sudden cold event this fall although it obviously moderated later.

6.) A sudden influx of ground water or precip caused acid shock. (doubtful in our high alkalinity waters but it's not uncommon out east.)

7.) The ground water in his area is contaminated with something. I'm doubtful of this as you would have seen this earlier.


Did the dead fish show the classic appearance of environmental hypoxia? That is, the opercula flared and mouths agape in a desperate attempt to get oxygen?

It may have been one of these factors or a combination of them. You may never know.

eric, no they weren't, and they were stocked about 3 weeks apart back in Oct/Nov.

I asked the county health department a year ago where I could send water to be tested and they looked at me like I was asking for a 2 headed snake. They had no idea. "Why would you want to do that?"

I think you had a DO sag low enough to kill just the HSB and trout in probably the deepest water or a section of the pond. Ponds typically lose the DO in the deepest water first. Those species not 'trapped' in the low DO or those that ventured out of the stressful water survived. Trout and HSB require higher DO compared to other species in the pond. Vulnerable fish in the stressed area were 'trapped' and killed. I say the deepest water because the diffuser is 3-4 ft deep during winter operation and IMO mixing primarily the upper 4 ft of water of the water column. IMO Shallow water diffusers with gentle, intermittent aeration (windmill sheltered by trees) will result in stratified (chemical &/or temperature) layers. Post kill DO tests in the surface waters (0-4ft) will likely show DO is just fine, esp. true if sunny days have followed the kill. The DO was probably 'okay' in the upper 4 ft during the presumed winterkill.

This system is a low air flow unit. I strongly advise against using this air producer in this application due to: 1. pond receives lots or organic inputs creating a unusually high BOD. High BOD requires the strongest aeration possible. Sewage plants are examples. 2. pond is only 7-8 ft deep and has a low DO reserve. A shallow placed intermitent weak diffuser (windmill) in 0.7 ac increases the chances of stratifiation events. 3. this EL2 unit is a low air volume unit compared to the hp involved. The best choice for this application is a unit that has high airflow per hp such as a rocking piston or rotary vane. A pond this size needs a strong or high volume diffuser and several diffusers. IMO essentially the current aerator is undersized. Ideally I would consider a 3/4 hp RV unit with at least 3 diffusers for this specific application. Considering the history, I would operate at least 1 diffuser in the deep section (20% bottom area) all winter.

Cecil, you are freaking amazing in the deduction. Are you sure you're not an environmental scientist, with a pH also in geotechnical?

Scott, the reason why I ask you to get the oxygen metered for your pond is the same reason that Cecil described.

1. Ground water has a high level of dissolved oxygen regardless of the temperature. Soil strata create an oxygen rich environment, and when the water flows through there, oxygen content get saturated. When you pump it up, oxygen content get stirred, and oxygen remains or enriched, that is, if you're constantly introducing new ground water into the pond..or ponds. However, thermal exchange is my suspicion that shocked the crap out of the fish when new water is introduced if you're trying to fill the pond during winter. Other than that, possible pollutants, pathogens, or bacterial that targeted the fishes.

2. Little does people know, snow do bring in oxygen content due the crystallized structure creating aerated pockets. Snow falling on surface of water will mix oxygen to the surface. Ice will trap the oxygen, but as it melts, it dissolves the oxygen to the surface, thus, fish like to hang about 2 to 5 feet below the ice. Oxygen rich environment.

4. Fish tend to survive by readapting, but can only push for so long. Larger fishes have great affinity for adaptation, so, you don't normally see it until later..way later. If there are 5 conditions you must meet for them to be perfectly healthy, and fulfilled the 3, they will readjust until their bodies become exhausted. Small species will last 2 days observed in the wild. Some will last a year or two based on conditions.

7. Looks like there are signs of something that leech the oxygen content from the water if the fishes show signs of hypoxia. We need that oxygen metered from the pond. Could be a sudden CO2 shift and/or in combination to a nitrate affixiation from the primary pond that get the first wave of ground water.

One thing to consider is the amount of ground water and its temp entering the low cold water pond. If its low O2 and warmer you could get some strange mixing events not to mention the shock/stress effect on the fish. If so then that problem is going to happen again unless avoided by some means.

That's the reason we don't like Cecil taking long "vacations" from the forum...

Hey Leo,

1. Ground water has a high level of dissolved oxygen regardless of the temperature.

Teach and instruct us properly on this statement you made.

Thanks.

JKB, quite simple actually. Imagine the soil strata (soil layers) have various soil type as water go from top to bottom as it percolates from an above ground water source, say a lake, pond, forest ground, or even from rain. As the water moves from the upper layers to the storage area below, like an underground reservoir or aquifer, impurities within the water get pulled from the water molecules, creating a higher ionic charge within the water structure, as the water percolates deeper and deeper into the ground. Pure water, or water molecular structure, is not H20. Rather, it's H2O2. There are still active sites for the oxygen to grab onto other molecules that around the soil. In the deep soil, what molecules are available, beside carbon, silica, oxygen (exist between gaps of soil structures), nitrogen, stabilized metals, and various other inert compounds under extreme pressure? The only thing that being exchanged under high pressure, possibly high heat would be hydrogen and oxygen.

Constant battle to occupy the missing bonds between oxygen, hydrogen, and various other molecules, oxygen is one of the stubborn molecule that will not give itself up. It rather bind to other oxygen, nitrogen, or carbon molecules to find a way to stabilize itself out rather than giving itself up. It will attempt to rip the hydrogen from other compounds aggressive if needed. So, in an underground reservoir, without pollutants within the strata, what can water adhere to but more oxygen and hydrogen molecules? Ground water is loaded with dissolved oxygen.

Just take this scenario. How can underwater creature found in caverns deep in the earth survive with lack of oxygen if the water source don't contain enough dissolved oxygen to survive on? How can cave explorer manage to go so deep into caverns without having continually air supplies given to them? Oxygen get continually renewed as water pull oxygen content from the upper strata to the lower bedrocks and reservoirs.

Hope I don't overstep my explanation somehow..geotechs and geologists? Mind adding more?

Cecil Peed in his tank That's why we Love Him

Amongst other reasons

The shape of a H20 bond allows it to become H2O2 or something else. The bond looks like Mickey Mouse's head with the "ears" being hydrogen atoms and the face being an oxygen atom. The ear want to bond with something negative, another oxygen atom would suffice. While the face wants to bond with something positive such as more hydrogen.

Chemistry, Physics, and Geology are all great!

Can you show us some peer reviewed studies with final conclusions? Just on the one statement!

Reason being, is that a new PB Subscriber might read this stuff and think the planets aligned!

Please back it up!

We are not talking about caves either.

jludwig, love the Mickey Mouse's head analogy. True that oxygen would love to bond with something else positive, but when you're in an compressed environment that search for affinity to stability, which of the element is willing to give itself up more to become stabilized? If there is free floating carbon radicals, yes, carbon will give itself up. If there is nitrogen radicals, yes, it will go to the one that demands it. Oxygen will be aggressive, so, yes, it will pull others to itself. Metals, crystals, they've reached their inert states. Good luck with oxygen in ripping anything out from those other heavier elements.

This is why I'm concern about Scott's pond groundwater issue. It may not be the oxygen. More of the pollutants that exist in the groundwater, and possible thermal shock. Could also be high load of nitrogen/carbon content that cause affixiation, which displayed as hypoxia in the fish. Don't know until the metered oxygen come back.

LOL Planets are aligning aren't they in 2012? Understand completely about the proof required. I will search through my studies and notes again. The similar argument was made by the debate groups in the geology field study I was with brought the same counter argument, "Where's the proof?" over a decade ago. We did a massive collaboration with the geology, environmental, and microbiology department to find all the documented studies as far back as the local libraries allowed. A fun project that lasted nearly a year.

Groundwater is loaded with dissolved oxygen?

Why do most of our groundwater wells pump out water nearly devoid of dissolved oxygen into our ponds???

I think the officer is telling ya'll to take a time out.

You must be a mind reader!

LOL slowing down..slowing down to a stop. adirondack, they have the right to challenge any presented info of course. I know I would, if I see something off, even with a just bit of info is off. Please, be patient with me. I got so much files to go through. Old PDF and scanned image files are not as friendly for searches when I have decades of storage materials I have to dig through..just be patient.

But for a quick answer Rex, depending on where you're getting your groundwater, which can rob or give your water the oxygen content.

What's below you that make up the soil strata? What's around your underground water source which may rob the oxygen content?

For now, I step back to look through the myriad files. Always good to have backup from geologist and geotech group.

Leo your info on ground water O2 has really rattled the prevailing thought on ground water, looking forward to more facts on the subject, it might almost be like the time people found out the earth wasn't flat.

Or when the earth revolves around the sun...

Rex, I like your avatar......

Bill Cody where is your famous line again
"It all depends"
I think it fits in good with this ground water DO2 levels debate.

Leo, when I tested the water coming from my well (that is 66' deep) with Cecil's YSI meter, it showed 0.1 mg/l O2. But, test that water just a couple of feet away it jumped to 3.0 mg/l

I doubt that chemicals or pollutants are the culprit because there are 3 other ponds within 300-400 yds and they didn't have the winterkill. This property is away from houses, etc. The closest house to the ponds is roughly 1/3 mile, and there are 2 single family homes there. Other than those homes, it's probably a mile to another building.

Too few fish of too few species died for the culprit to be toxicity - pollution - contamination.

You lost me. 3 feet away - meaning at the surface 3 feet away after exposed to O2 or at 63 feet subsea still underground in formation ?

What Bill said - unless the pollutant is a natural element that those species can't tolerate but other species can. HSB can't take very low alkalinity but BG/GSF and others can. I don't know enough about trout to guess what they may be susceptible to.

The fish could have been in a catch 22 – seeking warm underground water temps but not able to stand the low O2 it contained – caught in a thermal O2 dilemma until it was too late. If they were near the bottom when the warm low O2 water mixed/descended/stratified they would have initially liked the situation until the O2 got to low at which point swimming up would have made the matter worse until they got to near the surface.

What baffles me is why the 2 species killed were cold/cool water species and not any of the warm water ones. What about the YP ?

Just an idea. At this point in time, we do not know for sure that all the other HSB and trout are actually still alive.Maybe some were sinkers and others floaters? Could it not be possible that only a percentage of the fish that have died actually floated? How long does it take for fish to gas up and float in cold water temps?

A good percentage lie on the bottom and never float. Frequently something begins to eat the dead fish before it floats. Alkalinity and hardness will not be low in the ground water in the region where esshup lives. The soils there will contribute hardness and minerals to the water. pH should not be a factor because trout can tolerate fairly low pH and tannins (wooded area leachate) in the water. Inflowing ground water will be warmer than water column water of 39F. However when seepagae ground water enters the pond it will be quickly diluted and blend with the regular pond water minimizing the impact of negatives and positives in the ground water.

Ok, I reread the o.p. Esshup says that the fish were in the bottom. Hey Esshup, at what depth were the fish when seen laying in the bottom. If they were in deeper water, this is my take. Ice cover, combined with reasonably clear water. I.e. small amount of phytoplankton to produce oxygen. Ice cover limiting oxygen absorption at the surface.Calm and overcast days. No sun reduced any photosynthesis that may have normally occurred. Calm = no aeration from the windmill, or oxygen absorption and mixing through wave action.

One more question concerning H2O and H2O2. I dont really get the chemistry part, but is your average DO meter capable of detecting H2O2? Where I'm going is 1. Can H202 be utilized by surface dwelling creatures? 2. I've heard it said that well water immediately absorbs oxygen from the atmosphere, or is it possible, that when the H2O2 reaches surface pressure the molecular composition changes, becoming H2O?
I have put fish in my well water before and survived a while without aeration. I also wonder if the notion of aerating all well water, at times has made some well water habitable merely by offgassing noxious gases I have seen you guys talk about, that were not detectable with the nose. I think it's called hydrogen sulfide. If water contains an elevated amount of hydrogen sulfide what are the effects on a DO meter?

I'm confused with ewest. Is the O2 jumps from 0.1mg/L from 66ft to 63ft? If that's the case, did you monitor any other depth beside the 2?



1. DO meter don't detect the H2O2, since it's unstable, creating odd reading. The meter is calibrated to detect only stable H2O structure.

2. H2O2 is unstable, so, it's always search for other elements to fill the missing spots. Any element that's willing to give itself readily or share, it will connect. If the covalent bond takes more energy to bond than the structure allows, it will search for other free radicals or elements to bond with instead. As you indicated, if well water reach a state of purified state, H2O2, it will hunger for the extra sites to be bonded to. So, yes, well water will want to bond with atmospheric elements, H, O, S, N, C, etc., or what ever it can get its hand on. This is why, in my field, we're monitor underground water supply so fiercely in California, since the underground water is susceptible to bind to chemical bloom, containing toxic compounds, that will taint our naturally filtered water supply.



I'll give you a thesis paper on that one. I believe the geotech engineer from our office wrote that paper just 4 years ago. I will ask to verify. You're in the ball park. In the meanwhile, I will continue to search through my external hard drive for the supporting files about groundwater with high DO. Please bare with me.

How I read what esshup wrote is that the water coming directly out of the well had a reading of .1 mg/L and then he took reading in the water a short distance away from the pump and that was 3.0 mg/L.

If I assume to understand Esshup correctly he is running water through a garden hose. At the outlet of the hose, he detects almost no DO. Then 3 feet away from the outlet of the hose he is detecting 3. If I am understanding this whole H2O/H2O2 thing correctly, the oxygen may be there, but is in a state that is not recognizable to the DO meter as Leo states.

My hunch is the water molecule is giving up one oxygen atom rapidly, causing a stable H2O molecule which is recognizable to the meter.

Do I have my chemistry correct?

H2O = 2 hydrogen atoms, and one oxygen atom.

H2O2 = 2 hydrogen atoms and 2 oxygen atoms?

So when the extra oxygen atom is released, you now have an oxygen atom that is a "free radicle", thus showing an "abundance" of oxygen in the water?

You win todays prize!

I was pumping water to my pond thru a 3" hose/pipe. The pond was low, and the water flowing into the pond hollowed out a 5' dia hole before it flowed out of that into the pond. Right as the water came out of the pipe it read .1mg/l, but 3 feet away in the pool of well water it read 3 mg/l. The water was falling about a foot before it splashed into the hollowed out pool.

This was in my pond, not the pond that winterkilled. The winterkilled pond is about 12 miles away from my house, but the ground and ground water is virtually identical. pH is right around 7.0

The fish that I saw on the bottom were in about 2'-3' of water, but the vast majority of fish were floating. There is between 3' and 4' of visibility. For most of the winter, the pond has been ice covered, although the ice hasn't been thick enough to walk on. What little snow we've had, melts within a week. The ice is whiteish in color, due to the melting/freezing cycles.

No fish smaller than 9"-10" were observed dead by me. The pond owner said he saw one dead fish that was about 4"-5" long, it was gone the next day when I visited the pond. I took some pictures of the pond, I'll get them posted tonight.

quote=JamesBryan]One more question concerning H2O and H2O2. I dont really get the chemistry part, but is your average DO meter capable of detecting H2O2? Where I'm going is 1. Can H202 be utilized by surface dwelling creatures? 2. I've heard it said that well water immediately absorbs oxygen from the atmosphere, or is it possible, that when the H2O2 reaches surface pressure the molecular composition changes, becoming H2O?
I have put fish in my well water before and survived a while without aeration. I also wonder if the notion of aerating all well water, at times has made some well water habitable merely by offgassing noxious gases I have seen you guys talk about, that were not detectable with the nose. I think it's called hydrogen sulfide. If water contains an elevated amount of hydrogen sulfide what are the effects on a DO meter? [/quote]

I think you need a little bit more specialized equipment to test for Hydrogen Peroxide. Here is some basic info anyway about the stuff.

H2O2-Fish

It is basically used as a disinfectant, kinda like Chlorine, but breaks down quickly, and leaves no residual. It is lethal to fish.

If H2O2 was of any use for supplementing DO, the Aquaculture World would be all over it.

Anytime you aerate water, it will off gas, so the oxygen replaces what got booted out, if it got booted out. Water is a natural "Sink" for some, so once you boot them out of the water, you may need to get them away via air movement or other methods. Not a typical problem in a pond

When I got my first DO meter. I went around and tested everything liquid, plus the air quality. My sisters well water was the worst. Heavy Hydrogen Sulfide, and it always smelled bad. DO was basically non existent, but when you fluffed it up with aeration, BINGO! It still has residual bacteria after the fact that put's a slime coat internally on anything, given time.

YUCK! Systems like that need to be flushed out once in a while. Maybe pumping a bunch of Hydrogen Peroxide in there would help!

You decide!

Yes that is correct. It is hard to describe the shape on here. All atoms want to get to equilibrium and it could be correct, Leo would have to answer that. I just know basic chemistry and a few other things.

Thank you Mr. Ludwig!You are a GENTLEMAN and a scholar!

Isn't H2O2 an oxidizer and typically unstable and very reactive in 'trying' to ozidize anything vulnerable in its path? How stable is H2O2 in a natural aquatic enviornment? I suspect not very stable.

Your welcome. I am young and in school so I might as well share my knowledge and contribute what I can to this forum.

I know what hydrogen peroxide is. I did not know what H2O2 is.I misread an above post when H2O2 was first mentioned. I apologize for my stupidity, and applaude the tender nudges concerning my mis-understanding!!

WOW! JKB, you must be a very lucky man! DO meter that can monitor water and air can be $$$. Wish I have that kind of cash to get myself something like that. Since you smell H2S in the water, that means you have either a bad vein of gas pocket, or something tainted the soil down below. Water there will be devoid of O2 period! Like I said, H2O2 will grab anything and everything that is willing to bind, which is H2S (hydrogen sulfide), since S is in the same class, but different atomic weight with O, they are willing to share. Acid rain..you got to love it. We have plenty of that here during the late spring, summer, and warm winter, like now, due to the dense smog at the inversion layer.

As you also mention about the "sink" part of the water, when anything that is heavier than O2, and combined with O2 into a soluble compound solution, it will sink. An example is the "heavy" oceanic/fresh water near the deltas. There are heavy water circulating near shore, as well as in sink holes. It's a whole different subject all together. Too long to explain.



You explained very well! You get a huge kudo point for remembering your organic chemistry. Only, and if only the oxygen is released as a radical in a stable water body, oxygen will be dissolved even more/faster than a polluted water body, such as one that has too much turbidity/total suspend solids/dissolved solids/pollutants/organics...



H2O2 may release the oxygen as a radical, and it's an oxidizer, but you have to understand, it's not an industrial strength oxidizer at 5% (retail with safety precaution), 10% (majority of cleaning solvent), or even food grade as high as 35%. No no..it's only at 1% to 3%. Still high enough to cause effects to biological in the short run, but too low to cause concern in the long run. The effects is not 24 hours based, but only 3 to 5 hours. Once again, due to all the fore-mentioned above.

YOU GUYS ROCK! Man, I'm truly blessed to hang in a forum that is active, no bloodshed, yet very in tune with sciences and the natural! KUDOS! Very rare to find such forum that don't exhibit arrogance, and loaded with helpful tips and dedication. If you need my contact for any reason, feel free to message me, and I'll be glad to give you my cell number. Call me any time for info, and of course, I will learn from you as well.

Rex, you'll be hearing from me, since you're the master of tilapia ;-) I would love to work with you in restoring project to the Salton Sea, while working in conjunction with the Department of Fish and Game and Salton Sea Authority. You made my day just being here. By the way, you are truly insightful to this species.

Leo we strive to learn and help others. Glad to have you join in.

For me, it's more of an honor to be apart of.

Fascinating point. Very important information.

I feel as if he has opened a great big window of understanding.I personally cannot wait to hear more of his opinions!! Thanks Leo! I've got some wonderful projects to start on now!!

Jim, thank you. I try to reinforce my opinions as much validated facts as I can. Please, challenge what I say on any given moment without hesitation if something feels off. We have bright minds in here, and let those minds show their very best so we can all learn.

Leo,

It's about "sinking" and "sourcing", and yes, it is a bit complicated, but I am not talking about sink holes here

The well at our old shop was 284 feet deep and in the Marshall Aquifer. The water coming out of that had DO at just under 2ppm, so ground water can have some DO, just not huge amounts.

The first DO meter I got was an Extech, and it measures both DO and %O2 in air. Most self calibrate in air. It was under 500.00

The unit going on my RAS in the "Master" control is made by Mettler Toledo. It is accurate in the low ppb (like 3 parts per billion) range, and will measure up to 50ppm. The sensors are rugged enough to withstand the higher pressures of supersaturating DO if I side stream Pure O2 thru a turbine pump. Although, I would place them right at the end when the water gets to the expansion chamber. Not wanting to go broke buying multiple meters, I am trying to find a remote I/O module on Modbus protocol that can handle +/- 500 nano volts. I have one at +/- 250 nano volts, but not sure how the meter converts volts in to DO. If my hunch is correct, it should work, if not, the inputs are isolated and have over voltage protection. Worst thing that could happen is wasting some time. I can't imagine hitting 50ppm (same as 50mg/l). This process requires a very thorough gas stripping of the water before injecting O2 at the turbine pump.

Interesting subject! Thanks!

Depends on what you are calling a creature.

Aerobic (+ O2) and Anaerobic (- O2) conditions exist, and "creatures" thrive in both of these conditions. They are adapted to it.

Trying to solve all of natures mysteries is a great motivator for us humans. Mistakes happen all the time, but that is to be expected.

We will never figure it all out, and that is where Humility comes in to play

Keep moving forward!

In my understanding, if you have H2S (hydrogen sulfide) you will not have any DO in the water. And vice versa, if you have DO there won't be any H2S in the water. I don't think they can exist together.

There are orgnaisms that can live in anaerobic conditions and I think they are all invertebrates.

Here's some pictures of the pond in question. IIRC, the pond is 250ish feet long from North to South, and the Southern edge of the pond is 160ish feet long (or wide). The pond tapers to about 60-70 feet wide at the Northern side of the pond, sort of a right triangle with the top chopped off and the corners rounded with the base of the triangle to the South.

If you see an orange surveyors flag in one of the pictures, that marked the high water line from 2011. When the pond was constructed, the majority of the dirt from the pond basin was spread out around the pond, creating an 18" to 24" tall grass covered berm around the pond, which is to prevent any surface water from running into the pond, and carrying GSF into the pond. In a wet Spring, the woods around the pond to the NE, E, S and SW will be flooded. From the top of the grassy berm to the water level now is approximately 4', and it's approximately 75' to 100' from the pond basin to the edge of the woods all around the pond. The woods is a mixture of Maple and Red Oak. The deepest area of the pond is the South edge to the Southeastern corner. The northern part of the pond is approximately 0'-4' deep, and continues at that depth over half of the length of the pond as you move Southward on the pond.

Looking from South to North along the Eastern edge of the pond


Looking from South to North along the Western edge of the pond


Looking from East to West along the Southern edge of the pond.
The winter diffuser is at the far SouthWest corner of the pond.


Winter diffuser in action. If I remember correctly, the wind speed was variable that day, 0-10 mph.

Nice unit! Wow, truly a great unit to have for quick field testing. That set someone back a pretty penny. We have the one that fits in a 55-gal fiberglass drum, only designed to do DO, turbidity, and pH. But that thing is so sensitive, it makes my head spin. We have to calibrate that thing constantly to get the best values without any issue. Remember, California's groups can sue the living crap out of you if you mess up field's data. So, we have to be diligent with our data collection to ensure everything is precise..not accurate..precise. We even have to document our calibration procedure with photos and logs. Sheesh.

As for the nano-voltage, similar to the method tested for specific conductivity, a slight charge is sent through the water, or in your device's case, a discharge is sent through the surrounding water to detect the ionized charge return with the sensor sitting at the center. For us, we collect 1 liter of water, use 5 different test tubes to ensure the value comes back with +/- 0.5% returns, without any outliers. The more O2 get ionized from the current, the higher the value return. Normally, the equipment sent out 4 to 5 different voltage cycle after every 15 minutes to get the accurate reading. Each voltage is set with calculation at different level to ensure there is no odd returns on the values. Once the value agreed, it will give the results with a 90% confident. Not sure about the unit you have, but it appears to be pretty well self calibrated.



Excellent deduction! There are creatures of the same species and family, but in different environment. Shrimps that live in fresh water can also be found in the shallow shorelines at the beach, to the depth of the ocean, and also in the secluded environment of the cavern miles below the earth. I'm taking shrimps as a primary example, because these are the only macro-invertibrates that are thriving well in all environment. The specimens that were brought back got placed under intense studies after spelunkers and field biologists extract them from the caverns below. Fresh air was in these caverns miles beneath the surfaces throughout the world. We had the same question marks over our heads just like you did, but our field geology and biology professors provided info to school us more properly. Under the anaerobic environment, with minimal food sources, energy required to be as passive as possible through either respiration process or activities, which triggers high level of ADP and ATP processes (energy production). Yeast would be great example, where when water and sugar is provided, they go crazy. Without one, they slow to a halt, unable to do anything. Anaerobic is either on or off. There is no adjustment to it. However, an optimal biological condition, it's much more efficient to have an aerobic system which can be slowed down, speed up, or just turn off and on completely at full speed, based on the conditions presented. Oxygen is available. Food source available, but scarce. So, the creatures in the cavern will slow down to a minimal to conserve fuel, trigger up the fight and flight response to escape and capture prey, consume, then slow down again. Same with the so called slime worms that hangs at the top of the caverns' ceilings that dangle string droplets of sticky slime. If anaerobic conditions exist down in the depth, there's no way to can trigger functions so readily to survive for millenia.

What gave us a good census of the DO level is the is the creatures we hauled up from the depths from the water sources or by harvesting manually. We try to understand their biological process, either be anaerobic or aerobic, in order to understand the environment below.

Once again JKB, great deduction and conclusion! Not a whole lot of people figure that out at a whim. A analysis like that come back about 1 week after the info presented. Only the keen minds will pick up the different environmental factors like you have. Keep that brain firing!

Bill, JBK presented the scenario for us with his well water, and aerated pond water, as well as California acid rain H2S can exist in the same water. O and S can rip each other H molecules when they need it, based on the total compound structure. In other words, if there are more H2S, then H2O get depleted since H2S is more abundant. However, H2O will try to retain itself in its stable form due to the constant O being neglected without the H to occupy its available space. Once there are enough O connected together, the O mass will then start to pull the H away from the H2S. It's a constant battle to obtain the H, until the O or S got something else to bind onto, such as other O, N, C, etc..Hope that make sense? I may give you guys headaches with a fast review of organic chemistry again.

Scott, did you a capture of the pond's bottom using a scoop or a rake to see what's at the bottom, such as debris, soil type, plant's matter, etc..It can also give us why the fish death occur beside a possible lack of DO or a thermal shock which may occur? The pond's bottom could also contain high level of various fines that could prevent the fish from absorbing oxygen through the gills due to the fines binding to the fish's receptor sites. I'm not a biologist, but I can bring your finding to the local staff at my place to give you a clear views of things. Sorry guys, I wish I can be more insightful immediately, but I have to collect info as I go to provide some definite info for you. There is a definite unseen scenario we haven't brought to light yet.

Leo:

No I haven't. As you can see the water is a wee bit chilly to be wading, and the ice isn't safe for walking. As I was mapping the perimeter of the pond on Wed with my GPS (I was trying to walk as close to the water line as possible) I did slip on the steep muddy bank and got wet to my pants pocktes. I said a nasty word or two.........

The GPS stayed out of the water and I finished the mapping. The pond is relatively new, being built in the summer of 2008. There are no underwater plants growing in the pond. The pond was dug in very sandy tan/yellow/gold colored sand. The bottom of the pond has 4 years of leaf accumulation/decomposition on it and that's about it. The pond doesn't have what we would consider a high fish density.

Scott, give me more on the yellow/gold colored sand. Do you have the sand analyzed or at least a photo of the original sand? Could it be a high level of crystallized soil, possibly quartz?

Wish I could have transport devices and just jump from site to site. So many fascinating sites to visit, but no proper means.

Leo, If you want, send me a PM with a mailing address and I can get out a priority box to you with a bunch of samples in it as soon as I can reach the soil again. We've gotten 10" of snow dumped on us overnight and this morning..

In other words, no analysis has been done.

Will do. Make sure it's dry! LOL Don't want it to leak all over the place.

Leo:

Here's a link to my pond renovation.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Main=12914&Number=151396#Post151396

In some of the pictures you can see some of the yellow sand that I'm talking about. I live in the same county, and have very similar soil types as the winterkilled pond. I dug my pond down to 22' deep, and ran into the first thin layer of clay at 12' depth. The winterkilled pond wasn't dug that deep, I'm estimating 10' below the orig. existing soil level, so if that clay is there, it was never reached.

In my pond, once that 12" thick layer of sand/clay was passed, it turned to sandy loam again. At about the 15' depth mark, we hit another layer of gravel, which slowly turned to solid grey clay at about the 19' level. Unfortunately, there wasn't enough clay dug out of my pond to line the whole thing.

I have fluctuating water levels in my pond too, but I think my pond hasn't winterkilled for one reason:

I have a larger volume of water in the pond, and it provides a bigger "bank" of D.O. for the fish during the winter if I don't aerate the pond during the winter (which I have done with no winterkill issues). I'm sure that I have a higher biomass of fish in my pond than the winterkilled pond in question if you just figure on pounds of fish per surface acreage. But, since my pond has 2x to 3x more water volume, that gives me more leeway in regards to available O2 for the fish if you calculate the pounds of fish per gallon of water.

Last year, my pond shrunk to somewhere around 1/2ac to 5/8ac due to the lack of precipitation and the resulting drop in ground water level.




At that low water level, I still had 11' to 12' of water in the deepest part of the pond, and no winterkill even without aeration.

Here's what it looked like a few months later after we had some water come down:


The water level came up roughly 65" from the low water mark. The stick that you see out from the tree in the first picture is a pipe with a 72" aluminum "yardstick" on it. It is compeltely out of the water by about 5" in the first picture. The water level on the stick was 59 3/4" at the time of the last picture.

Leo:

Thanks. Do you want me to dry the samples in an oven in a glass bowl between 200° and 250° or could the samples be damp, not dripping? In any case, they will be double/triple bagged in zip-loc bags.

Excellent! Looks like a few got it nailed on the head. Sandy clay, possibly 15% of loamy sand, with a nice shot of sedimentary quartz. Not sure how fine of the particle sizes it is. What was the last pH level you take for the pond's? Looks like the answer may be shoved into the light soon.

No need to dry it in the oven. Drying it in the oven will make it loose valuable info. Just sun dry, or room temp dry, is more than sufficient. No need it to be moist.

My accounting background leaves me feeling a little lacking in this thread!

Leo, last pH water test was 7.5 in my pond, although I cannot remember when during the day it was taken.

Scott, last few questions to paste the pictures all together with the local knowledge of the gurus here too:

1. What are your stocked fish minimal and optimal DO levels? Remember, it may be a certain level for the northern states but it doesn't mean it's the same for the central and southern states.

2. Temperature between incoming water and the deepest part of the pond on last noted measurement. It can be as far back an late fall or early winter. It'll be better if you have the latest data as the conditions allow you to do so.

3. Location of floating/sinking bodies. Will will give a very definitely detail how they're fighting until the last moment in life. There will be some offset of location found due to wind pushing the body, the general area of death shouldn't be too far off due to ice cap on water surface, or isolation of floating bodies due to icing water.

4. Be brave with one thing, which I forgot. Get a cup of the water near the inlet to the pond. You have to be brave on this one. Put about 2 cups of inlet water in a glass. Cover it up with a food plastic wrap. Nuke it for a good 3 minutes each time, for 2 times. Let it full cool down before removing the plastic wrap. Clean your hands well. Take one finger, dip it into the glass, and taste to see if there is a salty taste to it. Salinity will also be a key factor. If you have salinity test kit or meter, even better.

Ooo..so excite on the info. Such an interesting case!

I'm running out now, but will answer as much as I can when I return. Some of the data I have already.

In the pond in question with the winterkill, there is no inflow of surface water, just whatever groundwater filters thru the sand.

I have been following this topic with great interest. Leo has made some points with respect to DO2 in ground water that were new to me. It inspired me to do a bit of extra reading on the subject and a quick google search revealed that there is LOTS of information on this topic. A brief perusal of the literature demonstrates the axiom "It all depends" is correct. It appears that there are multiple variables at play including the location in the aquifer (both vertically and horizontally), rate of flow from the surface, rate of oxygen respiration (often determined by the concentration of organic compounds to be metabolized) and a myriad of other factors that would not be readily apparent without intensive study of the system in question.
Thanks to all the posters above for starting a very interesting discussion. If anyone is interested some of the sources are posted below.
Mike


Ground-water microbiology and geochemistry
By Frank Chapelle

http://info.ngwa.org/gwol/pdf/880245629.PDF

Study and interpretation of the chemical characteristics of natural water
(Google eBook)

It is a very interesting topic, just take it with a grain of salt!

Wishful thinking will not replace factual conditions!, and they are varied, many times over!

3 minutes till qualifying, gotta go!

Q4 rained out. Supposed to be good weather tomorrow. Field is set.

I hope that shed some more light on the winterkill.

Scott, looks like you have a similar case to Big Bear Lake (BBL) shallow pond areas, Lake Perris extended flood pond, and two small lake like ponds in the high deserts near our area. Here's the scenario:

1. You utilize an diffuser system within the 3' to 4' feet depth based on wind condition. Fish are now trained to go to the depth that's has the best oxygen supply.

2. As Sue indicated, summer time, oxygen at the bottom, not at the top, were consumed by biological decay (biological oxygen demand - BOD) by bottom dwelling organisms. Rather than fish remained at the bottom depth during winter to keep warm, there is no oxygen at the bottom, so they linger at the surface area, once again, trained earlier by the diffuser. DO at point of water introduction, 0mg/L. Point of DO 6 to 8ft away, 3mg/L.

3. Your soil, with just a quick glance to the best of my knowledge is great for retaining biological decays, as well as encouraged for biological growth due to nutrient retention and water diffusing down and out. Look at the surround tree groves. Beautiful growth during warm seasons.

4. Oxygen from the start was low before introduction of your fish, even though you're monitoring for the DO, which was in a low minimal standards for biological survival rate, especially for HSB. You stopped monitoring the DO, believing that the diffuser would induce enough DO into the water when there's not enough wind to stir up the water to infuse the water with oxygen. Quite few nailed that.

Now, this is the scenario that match the waters' (not so much at the Lake Perris' flood pond) conditions during cold winter when snow arrived and light ice caps were created, with similar to your pond's depths around the edge before the drop off. Rather than BBL shallow areas and ponds having diffusers, they actually have water from the local streams flowing in, or the water from the rain/snow melts flow in. The killer of the trout, carp, and catfish were the ice capped the water from the top, without wind from introducing oxygen into the water. The ice cap also prevent the water from the streams and the surrounding from being introduced into the waters. So, no DO in the waters during cold days.

Now, I'm not sure if your diffuser was running during the cold days, but it appears the fish kept on chasing for DO at the shallow area (trained from earlier) possibly where the diffuser was, since the DO was less than than tolerable DO level for HSB (minimal is 1mg/L). What made me curious is the single trout bellied up, without others being the same, unless you find others later at the bottom when the conditions allow to search. Last desperate chance was to swim to the opening the ice to create enough surface disturbance to create enough DO in the water for survival. Thermal shock between surface water temperature vs lower water temperature would be also an influence of their mortality. We did find fish tried to breath by jumping out of the water, and literally just lied on top of the ice through a small opening, yet, met their dooms.

For the time being, create a plan of approach. Have the diffuser go deeper to prevent the shallow death (I believe there was problem with fish death if diffuser in deep water from posts that I read?), and increase DO at the lower depth as DO migrate to the upper layers of the water during calmed conditions. Your water pressure may not allow you to push the air down that low, but you may have to alter your course of action.

Ensure that diffuser actually either sit on top of a large gravel bed, or sitting under a light gravel bed, to prevent pond organic fine debris from clogging the diffuser. The rock, if layered on top of the diffuser, will also increase the DO stratification in the water column.

I'll await for the sample to come, and I'll let the staff here take a poke at it, and if possible, have them use what we have available in our lab to see what's in the soil during their down time.

Hope I shed some kind of light to the darkness. If anyone see something that I cannot at the time being, please, chime in!

Leo, thanks for the time you are taking. There are 2 diffusers in the pond, one in 4' of water for winter use, one in the deepest part of the pond for summer use. They are switched when water temps are in the 40's. The diffusers are placed inside of 5 gallon buckets to prevent them from stirring up bottom sediment. The diffuser in the deepest part of the pond cannot be used during the winter because it will cool the water from 39°F to less than 35°F, and that could kill the fish as well, especially the RES. There are RES in the pond, and they might be the first to go with that cold of water temps in the winter. The pond is supposed to be a SMB/RES/YP pond, or BG would be stocked. SMB cannot keep up with BG fecundity.

In #4, I think the O2 was good at the time of the HSB/RBT introduction. The photoplankton bloom during the warmer months contributes a lot of O2 to the pond. The trout seemed to be happy, and when the owners son caught some for dinner, they fought well. The few that were released swam off very quickly, and didn't seem to be stressed after the fight from lack of O2. That was when the pond was still ice free.

Last year, without any diffuser running (well, the deepest diffuser was not closed 100% by mistake and couldn't be closed due to the valve being inaccesable due to ice) the DO in the pond, with a much harsher winter with heavy snow cover never dropped below 5.05mg/L at the bottom of the pond in the deepest water. The only difference between last year and this year is the addition of the HSB and RBT. I had Cecil's O2 meter to monitor the water in all the ponds on the property plus my pond last year. Looking at the data from last year, this pond (Pond #1) showed roughly 1.0 mg/L less O2 than Pond #2 consistently the whole winter. The assumption was made that since both ponds have approximately the same water volume, and that both ponds were stocked with the same amount and type of fish. that the GSF population that is in Pond #1 used up that "missing" 1 mg/L. Pond #3, which is approximately 50% larger than these two ponds, had even higher O2 levels for the whole winter.

But, pond #3 was dug in 2010, and had only about 30# of fish biomass in it. None of the ponds during the winter of 2010/2011 had the diffusers running during the winter.

Ahhhhh!!! Thanks for the explanation on the cool temp effect in the water during winter time aeration. I live in a warm climate, and aerators are not used in the mountain areas. So, winter time aeration to me is a new concept. I had a suspicion from reading the "fish death" with "winter time", but was not confirmed until now. I notice most ponds are in the 10ft and shallower, with the winter temperature below surface ranges roughly 5 to 7°F from surface. Some fish are not cold hardy, so, they'll belly up. So much info to acquire from the cold part of the country that is extremely in tune with the fish. Wish I have a teleporter just to jump to you guys to do close monitoring.

During the prior winters with adequate DO for ponds 1 and 2, were the ice caps generated by the cold weathers and were the diffusers running at optimal conditions as well (assuming that they were)? What were the DO level monitored, if there was any info on it. I'm curious between the DO between non-aerated level vs aerated level during winters before intro of RBT and HSB. It's incredible that they consume that much DO in the water over the GSF existing population. Just like our bodies, larger body require more oxygen for respiration purposes. So, the reserved DO may not be enough when larger bodies go introduced into the larger pond.

By the way, to continue with the #4 as you provide more insights, was the DO in pond #3 remained higher than ponds 1 and 2 throughout the winter with, or without, the intro of HSB and RBT? As researches indicated the HSB is a harder group of survivors down to 1mg/L of DO. Not so much with RBT.

Looks like there may be a bacteria or pathogenic element in the mix. Could you capture a few of the species for a quick observation to see if there is red sore disease (red spots and irritation sores on their bodies)? I will make note to prep some dye detectors for bacterial and pathogenic materials coming from the soil sample you're sending.

Truly Scott, you're making my day. So much fun entails in this discussion.

Leo:

When the O2 levels were monitored last winter, and found to be good, one of the ponds had a windmill diffuser running in it. Pond #2 was chosen to leave the diffuser on because that pond was almost the identical twin of Pond #1 in regards to pond age, depth, number of species and amount of fish stocked. Both ponds are constructed the same way, and judging by the surrounding trees, they both have the same amount of organic leaf litter entering the ponds.

O2 levels were checked in the deepest portion of the pond at 1' below the ice, 3' below the ice, and so on until 6" above the bottom.

Some cliff notes:
January 2011

Pond #1 7.5" ice, 6" snow
1' - temp 33.6°, DO 6.54 mg/L
3' - temp 35.3°, DO 5.68 mg/L
Couldn't measure deeper water due to thin ice by diffuser that wasn't shut off 100%. The diffuser valve was accidently left cracked open enough to create a wet spot or very tiny open area in the ice, no more than 2'-3' in diameter during periods of sustained winds. The same diffuser in pond #2 kept the ice open in a 20' to 40' diameter area around the diffuser. I don't think the diffuser in Pond #1 contributed much if any to the O2 levels.

Pond #2 windmill aeration in shallow area, same ice/snow as Pond #1

1' - temp 33.7°, DO 7.01 mg/L
3' - temp 35.8°, DO 6.69 mg/l
cannot test deeper water

Pond #3 No aeration
1' - temp 33.9°, DO 11.54 mg/l
3' - temp 39.2°, DO 9.01 mg/l
4' - temp 39.8°, DO 7.58 mg/l
8" ice, 6" snow max water depth 4.5'

My pond no aeration 5" ice, 4" snow
1' - temp 36.2°, DO 10.9 mg/l
3' - temp 37.2°, DO 8.95 mg/l
5' - temp 39.1°, DO 8.80 mg/l
7' - temp 39.2°, DO 8.72 mg/l
9' - temp 39.2°, DO 8.73 mg/l
11' - temp 39.2°, DO 8.71 mg/l

February 2011
Pond #1 11" ice, 4" snow
1' - temp 33.3°, DO 5.98 mg/l
3' - temp 35.2°, DO 5.55 mg/l
4' - temp 35.8°, DO 5.05 mg/l

Pond #2 10" ice, 4" snow
1' - temp 34.9°, DO 10.4 mg/l
3' - temp 37.9°, DO 10.2 mg/l
4' - temp 38.9°, DO 8.85 mg/l

Pond #3 11" ice, 4" snow
1' - temp 34.8°, DO 9.26 mg/l
3' - temp 38.6°, DO 7.71 mg/l
4' - temp 40.1°, DO 4.72 mg/l

My Pond 7" ice, 4" snow
1' - temp 34.3°, DO 10.4 mg/l
3' - temp 38.9°, DO 6.93 mg/l
5' - temp 39.2°, DO 6.91 mg/l
7' - temp 39.2°, DO 6.63 mg/l
9' - temp 39.3°, DO 6.48 mg/l
11' - temp 39.3°, DO 6.39 mg/l

This is all data that was before introduction of HSB/RBT. In my pond, I have a pretty high biomass of fish, I'd estimate at or exceeding 500#. No O2 data was acquired this year as I gave Cecil his O2 meter back. I added 50 RBT to my pond this year, sourced from the same supplier as the winterkilled fish, and stocked at the same time. No morts are observed in my pond this year, but I am running an electric compresser with the one membrane type diffuser set at the 7' to 8' deep mark.

On the winterkilled fish, there were no lesions, sores or any other visible signs that the deaths could be linked to a pathogen.

DATA!!! DATA!!! That is some awesome sets of data! You need a DO meter for yourself there Scott.

As for the data set on Feb of 2011, same diffuser setting cracked to allow a spot in the ice, say roughly 10 to 20% of total aeration capacity?

Passing the recompiled data on the Excel spreadsheet to the local staff for their input, while I get the info about the Jan and Feb aeration status.

Leo, yes on the diffuser cracked open, I'd say 5%-10% at the most. It wasn't even noticed until ice had formed and there was a "wet" spot in the snow. It was so little that it really didn't keep the ice open when the ice got thicker. It was enough to keep the ice thin, making walking to the deepest part of the pond on the ice too dangerous until the ice in the rest of the was over 8" thick, and even then I was VERY careful and had multiple back-ups in place to get out if I were to go thru the ice.

I was on the property adding cover to another pond and remembered to bring a fishign rod along. I tossed a small crankbait in the pond that had the winterkill. I walked around the pond, getting one strike from what I assume was a HSB. The lure felt like it ran into a brick wall, then nothing. There were small fish in the shallows, I think Gams.

But, in the SE corner of the pond, I caught 3 RBT in 8 casts. One probably would have tipped the scale at 3#. IIRC there's only 10-12 RBT left in the pond, so I caught at least 25% of them. (they were returned to the pond)

I think whoever said that some of the fish might have been caught in a low DO zone and didn't make it out was correct.

Hm..looks like the assumptions were on the money. Great job everyone for nailing the issue in the head.

So, the best bet is to deploy a netting across the presumed low DO zone during the winter to prevent another winterkill?

It would be interesting to know how often fish either get caught in a low D.O. zone or know enough to seek higher D.O. I say that because I had a catfish farm manager in Mississippi tell me that when they monitored D.O. in large catfish ponds at night, if the D.O. started to crash, they would crank up the PTO paddlewheels and the catfish would immediately head for the higher D.O. even in a 20 acre pond.

I can't chime in for everyone who live in the cold regions, and performed DO monitoring, but I do noticed for my colder mountain areas. Trout tend to search for food sources, and will venture into the low DO zones during day time, attempting to stay in the warm zone, then end up belly up due to the lack of O2 with no food in sight. Same for carp. They would do the same thing, searching in familiar grounds that normally have dense vegetation, but during winter time, plants died off, and they end up trapped in the low DO zone with no food insight. They were unable to return to the depth where the high DO was. They became easy scavenged for predators.

One fun study in North Dakota had transmitters in northern pike and walleye. As DO declined as winter progressed, the walleyes clustered around the openings from the aerators while the low-DO tolerant pike continued to use the entire lake.

The plan for this year is to install an electric compressor like the other 3 ponds have that had no problems. That should fix the problem. The airline and diffusers are already in place, just need to run some electric and make a vandal resistant enclosure.

Cecil, the guy I have grow my Tilapia to pond stocker size is also a huge catfish farmer producing over 1M pounds annually. He is Amish and has no electricity in his home, but has a $10M, fully computerized aeration system with DO monitors/alarms, paddle-wheels, liquid oxygen injection and massive powerhouse style agitators all on automated back up generators, just in case, that he has full control over from his smartphone...he commented how the fish will get stressed and and gravitate toward the aeration before the alarms go off and the system kicks on.

I find it hard to believe fish could get "trapped" in open water with no forage or low DO. The fish live there and know the patterns of their prey and when there is O2, especially if fish stocked densely for food production know where safety is going to come from in these production ponds after only one or two events.

Rex, this is where it gets extremely interesting. It's common knowledge for an aquafauna culture to live in a preprogrammed environment vs a free for all environment have there differences. This is only through my own observation due to my scientific needs for answers. Remember, where I fish, work, and play, all environment are non-monitored or intervened with gadget galore.

In private ponds, where aerators and monitoring equipment are used to introduce oxygen into the water in order to prevent private stocks from going south, the fish population will of course learn that there are sources of oxygen to head to when time of DO became a lack there of. What happen when you have a water body that has no such equipment to provide, and DO may only exist in a spot within that water body, in which all species compete for the limited DO within that area? Food sources became scarce due to competition, then what? They prey on one another, yet, once the smaller size preys have been exhausted, then how do they manage to survive without venturing to other areas for sustenance?

This is where my observation kicked in, and deduction had to be made based on what had transpired, and prior season's notes required for field analysis and eliminating possible and probably causes. What you're exposed to is a systematic protocols to save your stocks, or possibly lack there of. What I'm exposed is nature do-or-die scenarios. I take everything into consideration before presenting knowledge and facts, since I hate presenting something half hearted without a light of proof somewhere. Truly, it's hard to believe at time when you're working with controlled environment. But reality is, the truth can be harder to swallow when you're staring at it face on.

I'm always out to learn and acquire new knowledge and expertise. This is why I venture so hard far and wide to gain more knowledge to either improve on what I've learn, and debunk what I've attained, or utilize the info I've been shared with as is. Do share your view points, and know that my ears do listen, and my eyes are opened wide to receive the new info. However, your presentation of information is one sided, without considering the other side of the coin into the argument. Please, correct if I'm wrong in anyway. I'm always listening and watching for new experience.

Makes sense Rex.

Funny about the Amish. I have several Amish friends that had cell phones before I did. In fact I still don't have one! (I live near one of the largest Amish communities in the U.S.)

An Amish taxidermist friend has a Palm Pilot (I don't have one of those either) and was just telling me he was headed to the local library to get on the Internet.

Remember, this pond had a windmill aeration system, and it was cloudy/low to non-existant winds for a 2 week period. The windmill aeration system is spotty in it's aeration here due to the intermittent winds. It doesn't help that it's 30' to the West of a treeline that is taller than it is, and has another treeline about 75' to the South that is taller than the windmills too. Maybe it was spotty enough that the fish never realized where the O2 was the highest because it wasn't continuous?

Maybe enough larger fish died and that reduced the O2 consumption so the remainder of the fish lived?

All I know is that I'm really puzzled why some RBT survived while about 1/2 of the HSB perished.

Scott, that's why your situation bugged the crap out of me since I read up on your posting. I asked DFG personnel that I know for prior observation they noted, with those who work in fisheries as well. They're all scratching their heads when I mentioned about the HSB and RBT. All they could come up with the possible scenario was the RBT possibly had already adjusted to the environment before the HSB, and geared toward survival mode rather than hunting mode, allowing them to fit for survival over the HSB, which are pure eating machine.

The staff joked (with a hint of seriousness) that, even with low DO, HSB will forage to satisfy their need for foods over their needs for breathing. They even shown me a few photos of striped bass would swallow other species they recognized are of the same size as their own bodies, and bellied up. I believe they shown me a YouTube segment where bass of the same size would swallow each other alive, risking their own lives just to satisfy their needs to feed. So, it's not too far fetch where HSB would ventured beyond the areas of high DO to just forage, and rather risk dying than starving due to fierce competition already existed at the comfort zone.

Leo:

Interesting! The trout caught today were leaner, more resmbling a trout from the wild vs. a fed trout. Which makes sense because there is no pellet feeding program in the pond. I'll have to check my records because I think that both the HSB and RBT were stocked within a few weeks of each other.

The reason HSB were put in the pond was because of a Green Sunfish problem. Many small ones. The pond is slated to be a SMB/RES/YP pond, so the owner wanted to get the GSF out of there. There is no sign of YOY recruitment of either the YP or RES due to the GSF in the pond. Another pond of the same age, same stocking minus the GSF has signs of RES reproduction during the summer of 2011. No SMB have been stocked yet. I Fyke Netted the pond during the late summer/fall, and thought the HSB and trout could continue working on the small GSF all winter long. Plus the trout were caught on a small crankbait that somewhat mimics the size and color of the small GSF that are in the pond.

It's still undecided on whether the pond will be drained/killed and dug deeper, or leave it alone and add the electric compressor. Even if it does get dug deeper, the electric and windmill aeration systems will be in the pond.

I am impressed that some Amish are so up to date with technology. Back in the 50's a friend and I were fishing and the car was stuck in mud when we tried to leave. We walked for miles in Amish country (Indiana) (most were very shy and would just look out their windows at us) trying to find someone that had a car and could pull us out.

A friend's uncle was a veterinarian in the 30's in Northern Indiana and looked after their animals. He started buying up ordinary things from the Amish that were actually valuable antiques. He was worth millions when he died and my friend received a nice inheritance. Sorry for getting off message.