I've got a 4.8 acre pond that's 2.5 years old that has been ideal in every way until yesterday morning when i saw it had turned over. 3-400 dead CNBG and RESF and about 50 LMB, along with thousands of threadfin. This morning it's worse than yesterday.

I've been running 2 3" pumps spraying water in air since yesterday morning but not sure if they are doing any good. Seems that it got worse at night when dissolved oxygen is lowest anyway.

When I built my pond I asked the large reputable company that stocked it, and has since helped manage, fertilize etc, if he thought I needed aeration and he said no they didn't recommend it due to infrequency of pond TO and cost. I could kick myself for not doing what I knew was the right thing, which I had learned mostly via this awesome forum.

If anyone has any recommendations as to how I can mitigate this ongoing kill, please let me know. The management company told me that it wouldn't help to remove the dead fish, but I did so yesterday including most of the threadfin which I bagged and froze for offshore bait/chum. Needless to say I will be installing aeration at the right time going forward.

Thanks in advance and man does this suck,
Ronnie

I would definitely take out all the dead I could get my hands on. If left to rot they will add to the low O2 and retained bio mass in the pond.

Ronnie, your story strikes fear in the heart of this neophyte pondmeister! Looking back, did you see any signs that trouble might be coming? In particular, what was your water visibility? Did you fertilize? What pH level?

Not criticizing in the least, I'm just trying to figure out how I might avoid the same issue!

Anthropic, below are the conditions prior to the turnover:

Started fertilizing in March, 40 LB powder fertilizer (10-52-4 I believe). SE Pond did fertilizing and doubled normal 20 LB (4 lbs/ acre) application in March to jump start bloom. Same process as last 2 years BUT my alkalinity was much higher this year.

Had a beautiful bloom since early April and unusually warm late Winter and Spring. Secchi disk reading of about 18-20". I told SE not to fertilize a couple of weeks ago when they were scheduled to come. They came anyway and agreed that no fertilizer should be applied on that route.

Alkalinity was low (12 ppm) last summer so I applied 25 tons lime in October. Alkalinity was in the 40 ppm range last time I checked in early March.

Pond was stocked with 4000 CNBG 1000 RESF, TFS and FHM in October 2014. Stocked 375 F1's in June of 2015.

We had harvested around 300 bream past 2 seasons but no bass. Had electro survey scheduled for this Friday to develop a harvest plan for bass starting this spring. Had caught several CNBG in the 1.2 lb range. Caught 5.9 lb F1 in late March (full of eggs).

Have 2 feeders and use Aquamax 500. Only feeding about 40 seconds a day/feeder the past few months. I retired in March so cutting back a bit on non essential expenses

I saw 1 dead TFS on Saturday and had never seen one before. Didn't think anything of it. Friday, Saturday and Sunday were the 3 windiest days that I can recall strung together in pat 10 years, followed by a cool front which brought 3.5" rain Sunday morning. The turnover occurred Sunday night resulting in the dead and dying fish on Monday morning. Turnover also killed the bloom and water is tannic colored and very clear.

Hope this helps....it helped me to retrack the steps and conditions. I think the only thing missing from my equation was aeration.

Thanks
Ronnie

Thanks DonoBBD, I'm cleaning 3 120 qt ice chests full of the salvageable bream and bass today, then on rotting fish detail tomorrow.

It was the cold front and rain that killed your bloom.

One other thing that could have played a part is how big of watershed you have.

For example, if you have a 20 acre watershed you have x amount of water flowing into the pond with the rain you had. But if you had a 200 acre watershed you would have 10 times x water flow into the pond.

The reason I bring this up is I have a 1/10th acre sediment pond that catches about half my watershed and filters it into my main 3 acre pond. It has been very productive at raising CNBG and RES for forage and stocking other ponds. But it does get huge flow through during even modest rain events. I'm sure this stresses the fish at times. A very large flow through of cold water would make more difference than a small addition of cold water from rain.

Just one more variable in your equation trying to figure out what the problem was and how to prevent it.

The weather , rain , temp are the cause. the low pressure system like that can cause the problem. The bio load in the pond run at high capacity also is a factor. Aeration would have helped. Higher alkalinity is a plus in such situations.

Eric,
Can you explain a bit about why higher alkalinity would help in a turnover situation?
Thanks,
dan

Proper alkalinity reduces stress associated with ph swings (see chart below). Fish under stress use/need more O2 and are more likely to succumb to other stressors. Alkalinity charts.

Min. of 20 and best range is between 75 and 200.

Yeah I was so glad I turned my air up fro 4 hours to 8 about a week ago. I truly believe keeping your water mixed in large rain events helps a lot when it comes to fish kills.

RC

I appreciate all the input and responses guys. A couple of pre-turnover conditions that I forgot to include:

Pond watershed is about 35 acres and about 25 acres of this is a hay field. My hay man fertilized the fields in early April. The rain last Sunday is the first heavy rain we've had since then.

I mowed the banks for the first time this spring 5 days before the turnover. I mowed with a bat wing which doesn't throw much toward and into the pond, but a fair amount of vegetation did lie in the water on the banks and I assume the decomposition process had started.

I've never sprayed any herbicides around my pond. I'm trying to avoid that if possible and it's been plenty of work, mostly pulling up primrose. May be futile but I'm going to manually combat until not practical.

Thanks again,
Ronnie

PS - I'm hoping the kill is over and I'm estimating I lost ~500 bream and ~100 bass. More heavy rain coming within the hour so I hope that this doesn't trigger any sort of relapse?

Sorry to hear that Ronnie, There are a lot of catch 22's to having a bigger pond. I always wanted a bigger one myself mine is only 1 acre but when things go wrong mine is so much easier to handle and usually less expensive. The more I look at it I'm glad my pond isn't as big as what I first wanted...lol

Good luck in this rain and keep us posted.

RC

how deep is your pond?

It's about 13 feet deep at full pool in deepest spot at toe and middle of dam. And about 8-10' deep in 25% of the surface area. Other 75% is about 4' average depth with range from 6' to 2'.

I can relate to that RC because I initially wanted to build mine 7 acres and that would have compounded my current issue))

Hmmm that's interesting. If memory serves me right I think it's been said that up to 8 feet you really don't have to worry to much about thermal issues or turnover... I may be wrong on that but I thought that's what I heard. Maybe that's why you only had a partial fish kill as it only hit the 13 foot area? Between all the rain you mowing and lack of sunshine... it just had to give somewhere.. Of course pros please correct me if I am wrong but don't D.O. issue thermal issues and turnover happen more in water over 8 feet?

RC

The other thing you may have to consider is with all the fricken rain you may have had something get into your pond that the fish did not like.

RC

I think your right on that RC, which I believe is likely why the management company didn't initially recommend to install aeration. Interestingly the worst area of the kill was in 2 of the shallower coves but maybe the fish moved to them seeking DO?

Since the entire 35 acre watershed is on my property and I use very little or no herbacides, etc or any thing else that could be harmful, I'm doubtful that any thing got into the pond. Plus with the bloom kill, it appears to be a classic case of turnover from my lay perspective.

Got over 5" of rain yesterday and last night and I'm heading to check pond. Hopefully it wasn't an acidic rain low in DO.

The other thing that comes to mind is temp change in the water. Maybe all that rain was so much cooler it just cooled your pond down to fast specially in the shallow areas. I don't know just thinking out loud. That is another reason I like having my air running during heavy rain events to help keep a better all around temp of the body of water.

Fresh water fish are more adaptable to water temps changes but to what extent before they start having issues? It may very well been a combination of these things that did you in.

If you can afford it I would definatley get air in your deeper spot in your pond and maybe one more setup elsewhere in the pond.

RC

I have not heard that about 8' depth. Turnover can occur in any unaerated pond if the conditions exist. Cold rain can cause a plankton (source of O2)die off which will reduce O2 throughout the pond. Also debris washing in can cause available O2 to be used up in decomposition causing a fish kill. Cloudy days can also be a factor as plankton producing O2 is much less productive. Large temp swings can also cause problems for the same reason as cold rain. It sounds like several of these factors were at work in this event.

Ewest what I have read in some literature (I believe from some governmental agency literature) is that in 8' or less they consider the wind will generally give enough water circulation that aeration is not beneficial.

I think most here on PBF would disagree with that statement, but I have seen that stated in literature.

As I recall they were also not mentioning anything about pond capacity being pushed with artificial feed. I got the impression they were talking about low management ponds to begin with. We know how some of the "official" recommendations are way behind the curve of actual practice.

I suspect their statement is true a good share of the time. I know in my location where my pond is open to the southwest and gets good Kansas wind "most" of the time if the pond were not being pushed with feed AND the pond was fairly new with little accumulated problems wind circulation would be fine 99% of the time. But where I feed and push production it is that 1% that I am worried about.

Few ponds are aerated around here and I have never heard of a fish kill (although I am sure there are some) but maybe 1% of the ponds get fed artificial feed and some sort of active management.

I think the more a person manages a pond and pushes production, the more he has to manage it to prevent problems. Including aeration in lieu of relying on the wind for keeping a pond de-stratified.

Thanks snrub and I agree with your comments. Aeration is not prevalent here either. Most ponds are not pushed (run at high biomass). Almost all ponds turn-over. The idea is to not let them go low DO when they do turn. In waters I am aware of turnover happens twice a year at least with the changing of the seasons. Most do so in a manner that low DO does not kill the occupants. Its the odd/unexpected events like those in this thread that make us all cautious. With the terrain here and the low winds the potential for problems increase.

Yeah I wasn't sure on the turnover part... Thanks Eric for correcting that. Good to know.

RC

I think I have already had two turnovers this spring due to high sustained winds, cooler than normal fronts, and rain. I am not heavily feeding on a sustained basis yet this year. After these events, no fish kills, but the CC don't come up for food for a day or two. The BG never stop feeding through these events though. High winds again today are nearly pushing whitecaps on my two 1/4+ acre ponds. No aeration.

EW, Thanks for the explanation on alkalinity and stress. I guess it's time for me to check my alkalinity again.

Playsomehonk, I'm sorry for your turnover event. I'm heading to my pond in Pearl River County tomorrow and I haven't been there since the mid-week storms and hoping I don't see anything like you've seen. Good luck in your recovery!

Best of luck DJ. I asked some folks in my area who have ponds and no one else had or knew of another kill.

Post kill update: As folks who have experienced a kill told me, it usually looks worse than it is and I hope that's the case with mine. The BG stopped on feed for 2-4 days but are back on feed aggressively as of yesterday.

If most of the fish that died floated and were visible, I estimate I lost 4-500 CNBG/RES and less than a hundred bass so definitely not a death blow just a solid punch in the eye)). Most bream and bass were larger size and very few small fish were killed. Threadfin took a big hit but I don't know what percentage died.

I told Management company about my hay fields being fertilized and they said that the high N2 could have contributed to the plankton kill...but I'm not sure how? Maybe burned it? Recommended that we seek a ~24" reading leading up to fertilization of hay field fertilizing next year. I had a16-18" reading this year around time fields were fertilized in April.

You guys are full of knowledge and experience and my thanks to all for taking time to provide the excellent input. I've rescheduled my electro survey for later this month and will update findings then to close the loop. Now I will be reading up on aeration systems thread.

Ronnie

It doesn't have to be a turnover. In an 18 ac "pond" that has a max depth of 8' that I used to manage, they had both summer and winter kills. The HOA didn't have a large enough budget to allow installing an aeration system in the whole pond, so we did 1/2 of it. The next year they experienced a summer kill in the half of the pond that was not aerated........ Visibility was around 18" at the time, and this is the year following a summerkill then a winterkill.

So to me, aerating even a relatively shallow pond will help minimize fish kills due to low O2 events.

My BOW has a standpipe system, 9 5/8 inches, that takes water off the bottom near the dam (about 25 feet deep). Most of the year the water runs out the pipe 5 - 15 gallons a minute due to a couple of small creeks, though during prolonged dry spells the flow stops (creeks still flow a little, but not enough to keep up with evaporation).

During large rain events, such as we've had the last week, water gushes out the pipe. Fortunately, only once did the emergency spillway come in use a couple of years ago.

Here's my question: To what extent does taking water from the low DO bottom layer help protect against fish kills? Does it make any difference at all? I know it's better to keep high O2 & fertile top water in general, but never heard any discussion about relationship to turnovers & fish kills.

Any thoughts?

Your system improves water quality. It helps reduce turnover but does not stop them. Turnover is mostly temp related. When turnover occurs rapidly if the deeper water is poor quality (low DO) fish kills may occur. Proper aeration makes the entire water column sufficient for DO purposes.

Thanks. That's what I thought, but needed some confirmation by people who know a lot more.

Even though pretty new, my BOW not only stratifies, the bottom layer can become nasty. A year ago the water coming out the standpipe smelled like rotten eggs for a few weeks. This was during a prolonged hot & dry spell.

Will have to aerate at some point. I have an 80 yard (not feet) long island in the middle, which obviously reduces natural wind driven oxygen exchange, something Bob Lusk pointed out several years ago. Haven't done so due to lack of electricity and extra $ to pay for system, but now that the fish are growing and the pond has become more fertile I'm gonna have to bite the bullet.

The smell you noticed is common. I would not worry about that one factor. One way to help some is in winter drop the water level just before a big rain event. Another help would be to keep the alkalinity up if possible.

anthropic, read this article. Hydrogen Sulfide While it is aimed at aquaculture, it is also related to your pond. While a turnover reduces the amount of dissolved O2 in a pond, it also mixes Hydrogen Sulfide and small amounts are toxic to fish. That's why there is a slow start-up with aeration systems in ponds that are stratified.