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Old 08-18-10, 04:12 PM   #21
clewis1014
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I have a friend that lives on the river below Horseshoe Bend. He said as of late (I talked to him yesterday), he has observed numerous dead trout washing by his place. He is kind of at the end of the line so he could be seeing fish from all over. Some were “nice size”, he said. Not good……….

Do we need to start talking about restoration at this point. How much luck are we going to have getting TVA to foot the bill? We need to have a plan in place! Could be a floating stocking so the fish would not be concentrated at the regular “meat holes” and would have a better chance of carry-over….
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Old 08-18-10, 04:55 PM   #22
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Default dead fish

clewis,

See if you can get your hands on some photos of those dead fish. It's too soon to give up on the river. It is a river on the brink and we can still push it the right way. The slower draw-down and increased oxygen still gives us hope. All we need is to hold out untill the weather cools a bit. TU, the DNR, and the local paper and citizens have been giving the TVA an earfull. TVA's most recent statement said that there has been no evidence of trout being harmed by the current drawdown. A dead fish pic would go a long way on the front page of the paper up here.

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Old 08-19-10, 12:45 PM   #23
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I will see what I can do. This guys is in a bad spot professionally and may not/ could not take them for me but would let me take them. Lets put out some feelers to other members soliciting honest pics of tailwater fish kill. If the TVA is playing games, screw them!

“Wanted”
Honest, un-staged photos of dead fish from water temp rise due to lake draw down on the Toccoa tailwater.

Please include:
Date and time of pic (digital stamp would be best).
Location
Water temp if available
Author of pic (optional)

Please email pics and short narrative of how fish was located to ___________.
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Old 08-19-10, 04:37 PM   #24
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Water temp at Hogback yesterday was 73 at 5:30pm with full generation.
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Old 08-19-10, 04:39 PM   #25
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Looks like the break in generation is over. Turning the jets back on tomorrow and Sat.
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Old 08-19-10, 08:56 PM   #26
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I spoke to the Regional Director of American Rivers today in Columbia SC. I explained our situation here and the TVA moving forward with the draw down in spite of the DNR recommendation to wait.

It looks like they are very interested in what is happening here. Check out the link below. This organization has had tremendous success in dealing with Hydo Electric Fisheries like the Tail Waters. They are excellent at finding the chink in the armor. I am asking for consultation from them at this point.

We have a meeting tomorrow at Unicoi Outfitters to discuss this topic among others. This near tragedy or maybe still to be tragedy may be our opportunity to make some great progress with this fishery. I agree with Bill O 100%. We need evidence. Start taking as many photos as possible.

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Old 08-19-10, 11:08 PM   #27
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Quote:
Originally Posted by Trout Addict View Post
I spoke to the Regional Director of American Rivers today in Columbia SC. I explained our situation here and the TVA moving forward with the draw down in spite of the DNR recommendation to wait.

It looks like they are very interested in what is happening here. Check out the link below. This organization has had tremendous success in dealing with Hydo Electric Fisheries like the Tail Waters. They are excellent at finding the chink in the armor. I am asking for consultation from them at this point.

We have a meeting tomorrow at Unicoi Outfitters to discuss this topic among others. This near tragedy or maybe still to be tragedy may be our opportunity to make some great progress with this fishery. I agree with Bill O 100%. We need evidence. Start taking as many photos as possible.

Trout Addict - Duane Miller

www.americanrivers.org
Nice job Duane!

I checked the river temps this morning below hemptown (72 deg.) and Tammen Park (71 deg.) during no generation. With the recent rains washing the dry banks of Lake Blue Ridge, the river was really muddy. In fact, it was the first time I've seen the water really muddy right below the dam. I saw at least a half dozen guys fishing at Tammen despite the conditions and watched them pull in at least a half dozen fish - all fingerlings. Anyway, keep those reports coming!




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Old 08-20-10, 08:51 AM   #28
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Quote:
Originally Posted by Dragonfly Man View Post
A question I have for some of you more scientific-minded folks: It's my understanding that the amount of dissolved oxygen (DO) water can hold decreases as the temperature increases (colder water can sustain more dissolved oxygen than warmer water). If I understand correctly, trout might not survive lengthy periods of 75 degree f. water, but its not a direct result of being exposed this temperature per se, but because they suffocate from the decreased oxygen that 75 degree water contains -- Is it the DO levels, not the temp. that gets them? On the Toccoa tailwater, we've seen the temps rise substantially during the past week (from 64 f to over 71 f) but the DO levels have remained constant at a little over 8 ppm at Hogback. So can the oxygen infusion system at the dam keep the DO levels high enough for the fish to survive higher temps than would be possible in natural free-flowing stream

-- J Pool
Yes, you are correct on the Temp/DO relationship. As water temp rises, its abilty to absorb oxygen (and other gases from the atmosphere) decreases.

I would like to know what type of DO tester you are using. From what I know about water chemistry, a temp swing from 64 to 71 should reflect a change in DO.

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Old 08-20-10, 07:44 PM   #29
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Saw at least a 22 incher float by my place today just as the generation started- dead as a doornail! No camera but my phone and it was too far away for a decent picture. Spoke with a couple kayakers who said they saw 4 or 5 good size fish dead as well. So are the big ones the first to go in the chain of events?
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Old 08-20-10, 08:22 PM   #30
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Default Critical Thermal Maximum

Here is part of a response from John Damer when asked about water temperatures and dissolved oxygen on the river:

Thanks John for the information!

The interactions between water temp, DO, and trout are very complex, but for the most part you are both right. When the water temp goes up, the water cannot hold as much oxygen as it did at cooler temperatures. Here is a table I found on the internet that illustrates this point.

Relationship Between Temperature and Oxygen Solubility

Temperature(degrees C) Oxygen Solubility(mg/L)

0 14.6
5 12.8
10 11.3
15 10.2
20 9.2
25 8.6

Keep in mind that trout usually require at least a DO concentration of around 5-6 mg/L for survival at "normal" temperatures. Notice that all the way up to 25*C (or 77*F), water has the capacity to hold that level of DO and more (up to 8.6 mg/L according to the chart). But, the metabolism of a trout also increases at higher water temperatures, increasing its oxygen demand above that 5-6 mg/L level to some degree,say to 7 mg/L at 25*C (just a guess, since I am having trouble finding any research that actually tells me how oxygen demand of a trout changes with temperature). We are getting close to that 8.6 mg/L, but still not there.

Now, in a river there are lots of things living in the water (fish, invertebrates, bacteria, plankton, etc.). These living things are using oxygen for respiration. In a typical stream, this keeps the actual dissolved oxygen level lower than what it potentially can hold. This is especially the case when the water is slow moving (pools, eddies), as opposed to faster water where new oxygen from the air is being mixed-inall the time (riffles, cascades, etc.). Also remember that the low flows that usually occur with high temps also mean less of this mixing.
So, to answer the question asked by John "Is it the DO levels, not the temp. that gets them?", for a natural free-flowing system the answer is,Yes. Low flows, high temps, and low DO concentrations usually occur together in the wild and contribute to the death of trout, but the ulitmate factor that is directly responsible is probably most often dissolved oxygen.

Of course we are not talking about a natural system on the Toccoa tailwater!

By injecting pressurized oxygen into the forebay of the reservoir, TVA can keep DO levels artificially high; at or even above what was listed in the chart shown above (supersaturation). It is our (DNR's) hope that TVA will be able to keep those DO levels elevated enough with their oxygen injection system that mortality will not occur as a direct result of low DO.

Just like every other fish, trout have a Critical Thermal Maximum (CTM). Simply put, this is the maximum temperature that a fish can tolerate before it becomes disoriented, loses its ability to swim upright, and ultimately dies. The CTM is different for each species, and even for individuals within the same species. CTM also depends on what temperature the fish is acclimated to, how quickly the temperaturei s raised, and on any number of other stressors. This makes measuring CTM very difficult, and when you can accurately measure CTM under one set of circumstances it may be different under another. With all that being said, CTM for rainbow and brown trout are usually reported as being somewhere in the mid to high 70s (F). Brook trout are less tolerant, with CTMs in the low to mid 70s.

Last edited by Becky Hulsey; 08-20-10 at 08:29 PM.
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