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Joined: Aug 2014
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I'd like to propose a theory/question and get some thoughts.
What is more critical for winter survival of fish, adequate DO levels or removing Hydrogen Sulfide and other poisonous gases?
In winters 2017-18 and 2018-19 we recorded DO levels of ~.8 PPM (using a YSI PRO ODO DO meter) and yet I had trout survive. The readings have been very similar both winters with .8 PPM of DO and water temps in the mid 33 degree area. In both winters I struggled to keep a hole open in the ice for long stretches but had aeration pumps running. The same scenario is playing out this winter. I am now very certain that the air is escaping the lake somewhere I just cannot figure out where. I am assuming the air is reaching the shore somewhere, maybe in multiple places, and escaping, but leaving no visible hole because of the deep snow. With no hole open there is no oxygen transfer to the water hence the low DO levels BUT with the air escaping am I still removing toxic gases from the water and this is allowing the trout to survive???
The trout either manage to find a pocket of water with somehow acceptable DO levels OR the extremely low water temps allow them to survive the low DO conditions. I am wondering if they are surviving low DO AND toxic gases or if I am at least removing the poisonous gas.
This will be my 7th year really working the lake up there and I am always still scratching my dang head. #notverysmart
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WBJ, why can't it be both? Adding O2 and displacing H2S at the same time. Doing both at the same time is working for you from what I have seen from your reports here. H2S is a very deadly gas, it will kill a human fast. We deal with it when drilling for Oil and Gas and it has killed many a persons on drill sights over the years. Then again, without O2 we would also die.
Please continue with what you lean, passing it along to even us southern guys. We learn from what have done in those Colorado Mt's.
Last edited by TGW1; 04/07/20 07:25 AM.
Do not judge me by the politicians in my City, State or Federal Government.
Tracy
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The trout either manage to find a pocket of water with somehow acceptable DO levels OR the extremely low water temps allow them to survive the low DO conditions I think it probably isn't black and white but rather gray instead. In other words, I think both these contribute to the winter survival of your trout. It occurs to me that you do not take DO measurements over the diffuser. Seems a potentially life-threatening situation if the ice were thin there. The temperature of the water is near freezing at a temperature where the potential for saturation is at its greatest. This means that the absorption of oxygen that you are pumping into the lake it is at its most efficient. If enough oxygen is absorbed to meet the lowered demand then the aeration creates a refuge where your fish are concentrated. Its not enough to add DO to the whole lake but sufficient to supply the oxygen demand of the fish in the refuge that the aerator may create.
It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers
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Thanks for the input fellas!
The fact that the actual air that is being pumped and making the plume adds almost no O2 to the water is repeated over and over again on the forum. At one point I had been ASSuming that without a hole in the ice I might as well turn the aeration off, but then fish survived. I had not really considered the fact that the plume would add an increasing percentage of its O2 into the water as the water temps dropped.
I knew the aeration was helping because fish were surviving, just not sure in what exact way.
Last edited by wbuffetjr; 04/08/20 06:56 AM.
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When checking my DO in the water plume at the diffusers I find the Do is lower than the water checked around the pond. Just like u said found in this forum. I contribute this to the plume moving water off the ponds bottom or from deeper water.
Last edited by TGW1; 04/08/20 07:06 AM.
Do not judge me by the politicians in my City, State or Federal Government.
Tracy
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Tracy I have found the same thing in the summers. MAYBE things are different in the winter?? I don't really know. All I know is trout are supposedly toast at DO levels less than 3 PPM and mine are surviving at .8 PPM.
Like usual up there, I see Mother Natures results and I scratch my head and wonder how the heck that happened or what the heck is going on here!
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Tracy I have found the same thing in the summers. MAYBE things are different in the winter?? I don't really know. All I know is trout are supposedly toast at DO levels less than 3 PPM and mine are surviving at .8 PPM. The lake is at 0.8 PPM. I'm at a loss as to how aeration would lower the DO below this level in the plume. Here's the part that may be missing in the analysis of the DO measures of the summer time plume. While you have established that the DO measurement in the plume is lower than the rest of the BOW, you haven't provided evidence that water in the plume isn't dissolving oxygen and increasing in DO. I think that it is different in the winter. The dissolution rate of oxygen is greater at colder temperatures particularly when DO is low and well below its potential saturation. In the summer, water brought to the surface continues to dissolve oxygen from air interaction as it spread outs. This can't occur in the winter when the water is frozen and light is prevented from entering the water. It makes perfect sense to me that water near the top of the plume in a frozen snow covered lake carries the most oxygen. In the end, there must be water with sufficient DO or the trout would die. If we were to agree that the aeration lowers DO instead of increasing it .... then I would agree that there was some factor other than low DO killing the trout when the lake was un-aerated. There are I suppose other possible explanations but the simplest and most plausible to me is that sufficient oxygen from the pumped air dissolved to support the trout.
It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers
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jpsdad - I have only measured DO in the plume during the summers. Never in the winter for obvious reasons. In the winters we never even get close to the plume - just too nervous.
In the summers measuring directly in the plume usually produces a lower DO number. I assumed because it is bringing up the low DO water from the bottom.
It does make sense to me that the plume could have a higher DO content in the winter though.
Gases like H2S are the other component IMO. I just have no way to measure them and truly know their impact.
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To be sure, there are other limiting factors besides the DO. Even in controlled experiments that test for the limitation of DO there can be other contributing factors that won't likely be replicated in the lake setting. For example, the production of CO2 in such an experiment as a respiration product of the fish. It is toxic and at increased levels may contribute to fish dying at more elevated DO than in water at lower CO2 levels. I think this could also be the case with other toxins as well. You've also, wisely I think, recognized the effect of cold temperature on the metabolism. The limiting relationships as they affect fish are multivariate and so its takes a considerable amount of testing to understand them. I think the proposition that aeration assists with removal of toxins in the water is a viable hypothesis. Whatever may be happening, aeration under the ice and snow is helping your trout survive the high mountain deep freeze.
Last edited by jpsdad; 04/09/20 01:13 PM.
It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers
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Joined: Apr 2020
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Sorry to hijack... I don’t know how to start a new thread! Am i crazy for wanting to put a waterfall disguised as a mini creek flowing into my 1/2 acre pond? I want to incread dissolved oxygen levels and maintain cool water temperatures. I want to stock trout for all season enjoyment. Any insight appreciated! Thank you!
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FFT - I think Ewest moved your post to a new thread for you. That will definitely get you more input.
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Thanks! I don’t know how to navigate the thread system (nor create my own for that matter!) Thanks!
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I was there once. With a little time you will get the hang of it! Good luck!
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