Pond Boss Forums INTRO Questions & Observations Winter kill 2021

I was torn whether I would even post this, because it's a downer. But some of the hardest earned knowledge in my life has come from my failures. So with that said, I'm pretty sure my pond winter killed. I went to pull a slat from my water control structure on my outflow, and was sad to see hundreds of dead fish. Of all age groups and species. Minnows, fingerlings, mature fish. BG, BCP, LMB. Around my outflow pipe I have a trash cage built from a hog panel (I posted about it back when I built it). And last year a sprayed the cat tails to clear open water space around the trash cage and outflow. So I can see the bottom very well, and saw hundreds more dead fish scattered all over the bottom. So I have the horrible feeling that thousands more of my fish are currently doing the same thing on the bottom all over my pond. Which makes me feel kinda sick. I even have a bottom diffused aeration system, with one diffuser in a shallow finger of my pond. I didn't turn it on till Feb 20th, and it took it 3 days to blow a hole through the 14 inches of ice we have. I hadn't ice fished since the first week of February, and when my brother in law and I gave it a another go on Feb 20th we didn't get a single bite. Nothing. In 3 hours. And we both moved around a lot, with different jigs and presentations. I was getting nervous then, so I used the cheapo underwater camera I have. I have used it many times before, mainly just for the fun of seeing fish. And I have found that even when I wasn't getting bites, I ALWAYS saw fish on camera. Every time. But this time, nothing. Not one. So that was why I turned on the shallow diffuser. But too late. I had formed some kind of idea in my head that since my pond hadn't iced over till Dec 25th, and then we had clear ice for 2 weeks before the first snow, that there would still be plenty of DO. Obviously no. Larger biomass? Probably. My LMB have been growing and reproducing and I feed a bit too. Two 2 second throws from about May to October. From a single hanging feeder. My pond is over 40 years old and highly eutrophic, so has plenty of silt on the bottom. Maybe my biologic DO demand from bacteria was a bit higher this year too? Possibly. Anyway, I'm thinking running my shallow diffuser all winter long, every winter, would have been smart. Sorry for the downer post. I hope I can prevent others from the same mistake.

Sorry to hear that, Luke.

Sorry for your loss Luke, hopefully you can bounce back from it. If its a full kill and you need to start over, would you do the same species again or try something new?

I had a similar experience this winter. I kept the aerator off most of the winter in hopes that me and the kids could go ice skating. Well we did get the chance and enjoyed all 15 mins of it. But when the ice started melting the 1st thing I saw were all the tiny bluegill scattered across the shallow sand bottom. I knew from reading this forum that o2 depletion generally kills from top to bottom (biggest fish 1st) and it was going to be bad. As the ice continued to melt I discovered more and more "floaters". I think it is going to be a complete fish kill, the only critters I have seen are crawfish, frogs, tatpoles, and a turtle. No swimming fish. Although I didn't see the grass carp I added in 2019, but I think they along with most of the others sank to the bottom. I had a kind of mutt pond with some pics attached. I think I'll go more by the book this time around. And, like you, I'll keep the aerator on year round.

We had snow on ice for a long period on all 3 ponds. I expected fish kills, but have seen no dead fish so far. Perhaps they all sunk? I did see very small fry in the shallows of one of the ponds, but large fish seem to suffer the most under low O2. Time will tell...

Aw, man, Luke. So sorry to hear that.

Two Rules to remember with fish kills:
1) More fish died than you see the corpses of, and
2) More fish are left alive than you would think.

Dr. Luke,

Sorry for your pond losses.

"I hope I can prevent others from the same mistake."

By posting, you are doing THAT for the next guy! If you have time, please keep the thread going as you learn more.


P.S. On a happier note - I loved your wood duck post.

I can offer up some cullable lm bass if you are interested.

My pond had walkable ice starting late december and is still covered in at least 8" of ice on 90% of the surface area - snow cover was roughly 10 weeks. 0 outlet flow period was 10 days - thats a pretty hard winter for ice thickness and snow cover. I bet you can make that pond bounce back rather quickly!

Luke and ajk, my condolences.

Reading this hurts my heart, guys.

I didn't get my shallow diffuser going before my pond froze this winter, and I feel like I got away with one.

Dr. Luke,
I'm feeling that pain pretty clearly over here. I was told that my pond also could hit its carrying capacity and do the same. I don't know what else to do. My kids want to skate and so at this point I'm not going to do shallow water aeration. This winter we had less time with snow cover and I was able to keep it cleared for skating. But I have ZERO plants so keeping it clear didn't really create any oxygen for me if you have zero plants right?? On top of it my groundwater table must have really dropped as the water levels seem to be done about 3'.

My questions for you to think about:
Can you check water for something besides low O2 that could have killed (meaning some inflow of some chemical or toxin for example?) That might be good to know before restocking
Did your water level drop a lot that set up concentration of the fish in smaller water meaning less resources or oxygen to go around?
For sure you need to sample your fish to see if it hit a TYPE of fish or a SIZE CLASS strongly. That might give some idea of the reason behind this
Obviously you can't measure oxygen levels after ice out as they won't correlate.

From your description it didn't seem like a bad winter or a situation where your ice and snow started at Thanksgiving and persisted till now so would it really be a sunlight issue?

One of my goal for this year is to try to find a more reliable way to harvest my spotfins and find a way to ship them. You are on the top of my list to offer some stocker SFS if you can't find them yourself in local BOW and are interested. It would make the most sense to stock them if you were going to spend this season building forage first. If you stock predators first it might be harder for a few stocker size SFS to survive.

Thanks for sharing your pain and we all can live through this with you.

CC, phytoplankton will put more O2 into the water than underwater plants will. Especially in the winter if sunlight can get to the water.

Dr. Luke, my condolences. My personal pond is less than 50% full with water due to the low water table here. Full pool is 1.1-1.2 acres, it's now .45 ac. I ran a winter bottom diffuser in the usual place but it is now in a finger instead of a bowl due to the submerged island no longer being submerged. Max pond depth this winter is 8.5 feet, it's usually 16 feet because going into winter the pond typically isn't at full pool. Max depth in my pond now is 18+ feet when the pond is at full pool.

I checked O2 levels in January and below 5' water depth they weren't high enough to support fish life (<3mg/l), that is with the diffuser running. MUCH higher biomass in the remaining water, and the diffuser being in a finger instead of more towards the main body of the pond.

So, I threw caution to the wind and turned on the diffuser in the deepest part of the pond, and opened up a 30' dia hole in 10 hours through 8" ice and a foot of snow. (What ice dome?)

We will see what things look like in regards to the RES in the pond, but with the pond 40%-50% ice free I don't see any morts.

CC-
I really appreciate you and everyone's thoughts. It sucks to have negative things happen, but if any learning comes from the experience it's a small win.
RE, your questions:
1. Can you check water for something besides low O2 that could have killed (meaning some inflow of some chemical or toxin for example?) That might be good to know before restocking: seems very unlikely to have been a toxin, as we have been frozen up and ground frost still in. The inlet fingers to my pond are flowing now but the fish were dead well before that started based on their decomp level.

2. Did your water level drop a lot that set up concentration of the fish in smaller water meaning less resources or oxygen to go around? We actually had full pool this fall and have kept it all winter. The water control structure I placed on my outflow pipe has been a great tool for controlling water levels and managing run off
and I am able to keep my pond 'topped off' all the time. I actually gained some water depth after I added it (about 8-10 inches).

3. For sure you need to sample your fish to see if it hit a TYPE of fish or a SIZE CLASS strongly. I had been already planning to repeat a shock survey this fall (because I wanted to sample size and class year data). But now it will just be to see who's left and in what age groups. *sad face* We had just started catching bass over 3 lbs with great body shape, so I had modest hopes to push some to 4 lbs by this fall. *sigh* Maybe with the next group. Or may there was a 'freak bass' that tolerated low DO better than the rest, or maybe found some tiny DO refuge.

Overall, it seems most likely I was at high end of carrying capacity due to my growing LMB and that I underestimated the biologic DO demand from bacteria in my old pond. It's a good thing to remember; never get comfortable with your guesses because 'you don't know what you don't know'.

I would love to take you up on the offer of some SFS. Just DM me when the time is right and will work out the details.

thanks Esshup. I have high hopes you got through the winter ok, and think your decision to turn on the air sooner rather than later was very smart. I watch WBJr's thread all the time about aeration at high altitudes in Colorado, and the discussion about super cooling. I have begun to wonder if maybe more species tolerate a great range of (low) temps than previously thought? There I go guessing again. I trust you and the other professionals and the fisheries biologists, and make every attempt to follow the advice given.

Augie, it's been a bit of a surprise how attached I got to 'my fish'. Even though I realize how little control I have over any of them and may not even impact their lives in much of a meaningful way with all the 'stuff' I do, I still felt pretty attached. And sad when you see the bodies all over. I've seen some pretty bad stuff this past year related to work stuff, so I haven't lost sight of the big picture. There's nothing more important than your family. But I guess it's just the joy of being on and in my pond and tinkering with 'my fish' has been so fantastic and uplifting, it's hard to think about starting over. But I will.

Sad to hear about the loss !
Keep us posted - interested to see if there are still fish left. Most times not all the fish die - see Theo's rule # 2.

Kinda worried about my 1 acre one. I’ve had a feeder going all winter. I went there a couple of days ago and did a one second throw. Nothing came to feed. Ok, I’ll check again. The water has been cold lately.

Then I took the 4wheeler to my small 1/4 acre one that has bg and 7 or 8 cats. They went nuts for the hand thrown feed. Now I’m getting worried about the big one.

Fingers crossed for your big pond!

I assume the small pond warms up more quickly in the spring. Perhaps, a slightly higher water temp has rung the dinner bell in that pond.

Hopefully, the fish in the big pond are just waiting for a little more warmth before they also hear the dinner bell.

Do you check water temps on your ponds?

Chief Wampum say.. "Pale Face send words from both sides of his mouth."

Response involving dots and casinos skipped in the interest of decorum.

Dr. Luke, one other thing on the brighter side is those removed fish equal removed nutrients from the pond.

Sorry for the loss, they are more like pets than food to most.

Thanks Brian. We've started hauling them away...by the tractor bucket load. I keep thinking how stupid it was not to run the shallow diffuser all winter.

So I wanted to update you all on the survival of some of the fish in our pond. Surprisingly (to me) we still have some F3 and bigger fish. And we have also caught some smaller class fish in our main species groups (BG, BCP & LMB). As expected, the majority of the LMB are fingerling size to 8". The BG show better size diversity. And the BCP are mostly around 6-8", with just a couple 16+" fish so far. However, the small class BCP have very fat bellies, which is both unusual..and nice to see. I restarted feeding, and we have some "customers" still. Hard to believe, knowing how many tractor buckets of fish I hauled off (at least 8, and my bucket holds two yards of gravel). I didn't realize how much I had been pushing my carrying capacity.

Some recent catches:

Gorgeous fish. Don't know that I've ever caught a BCP that big in my life!

I was really lucky with no winterkill this year. On the other hand, I now have a bass crowded lake & am working hard to harvest before they stunt. No matter what, we always face challenges & have to adapt to what nature hands us. Best of luck, and thanks for the wood duck streaming!