Pond Boss
Posted By: Cecil Baird1 Winter aeration: Still Learning - 03/07/10 11:27 PM
Perch and bluegill morts from three different cages.



Large 9 to 10 inch bluegills from one cage.



A view showing how far ice as melted so far as today of 3/07/10 looking out. High today was 49 F. Possible thunderstorms in the forecast. Ice is absolutely not safe to step on anywhere on the pond.





A view looking back the other way 3/07/10.




A view of typical water kept open during the winter give or take by the diffuser.




As you can see I lost some fish in the fish cages this winter possibly because they were too close to the diffuser I set in shallow water. However it's not as bad as it looks as I have lots more in the cages that seem to be O.K. In fact I am feeding my yellow perch in the cages with hydrated feed even though more than half the pond is still ice covered, and couple of the cages still have ice around them. The surviving perch look good and are feeding well. I also have large free swimming male bluegills and female yellow perch in the pond that are probably fine.

What does this mean to those of you that have ponds and use a diffuser in shallow water to prevent winterkill? Possibly nothing as your fish can stay deep and back away from any potential super chilling of the water if that indeed was the cause. The caged fish at about the four foot level didn't have that option.

One factor may have been that perch larger than 10 inches don't fair well in cages in winter. According to Dr. Perca (Bill Cody) in a recent email,

"I don't have good luck with perch larger than 10"-10.5" in my cages. Larger perch seem to be more territorial(?) and a larger percent have more body abrasion as they get bigger. I think it is due to interaction and competition in the cage. Any cage stress is not helped by super cooled water."

I'm considering putting my male perch that I typically kept in cages, in a seperate pond as with the female bluegills. And any fish that must be overwintered in cages I will put farther away from the diffuser. It also appears smaller fish fare much better (see below).

Some interesting observations with the cages and subsequent morts or lack thereof:

(The higher the numerical value the farther away from the diffuser).

Cage # 1 -- Had a low density of bluegills approximately 3 to 4 inches had no morts whatsoever. It was inside the edge of the ice or in open water a significant part of the winter closest to the diffuser.

Cage #2 Two year old gills 5 to 7 inches (not YOY) had about a 20 percent mortality.

Cage # 3 Larger mostly male YP and some females had about a 50 percent mortality.

Cage # 4 200 + small YOY 09 in number of 5 to 8 inches had 10 percent mortality tops.

Cage # 5 with large bluegills 8 to 10 inches I lost 7 out of about 25.

Cage #6 with a high density about 250 bluegills 3 to 4 inches I lost one.


Posted By: Theo Gallus Re: Winter aeration: Still Learning - 03/08/10 01:00 AM
 Quote:
Possibly nothing as your fish can stay deep and back away from any potential super chilling of the water if that indeed was the cause. The caged fish at about the four foot level didn't have that option.

I keep telling myself that, Cecil.

The ice is still pretty thick here, but I bet it'll be gone in a week, with 40's50'sand rain forecast. I'm keeping my fingers crossed that my fish will be okay.
Posted By: Todd3138 Re: Winter aeration: Still Learning - 03/08/10 01:13 AM
Wow, Cecil, sorry to see that much loss for you. Glad you had good numbers to start with though.

We hit 52 here today and had bright sunshine. The whole week is supposed to be really mild. I'm hoping I can make it out to our farm on Wednesday for the first time in approaching a month. There was ice when I was there last, but it wasn't terribly thick. I'll be interested to see if we lost any fish as the best pond, our small one, is really quite shallow across most of the pond with just one deeper area reaching probably 4 feet or so.
Posted By: Cecil Baird1 Re: Winter aeration: Still Learning - 03/08/10 02:16 AM
 Originally Posted By: Theo Gallus
 Quote:
Possibly nothing as your fish can stay deep and back away from any potential super chilling of the water if that indeed was the cause. The caged fish at about the four foot level didn't have that option.

I keep telling myself that, Cecil.

The ice is still pretty thick here, but I bet it'll be gone in a week, with 40's50'sand rain forecast. I'm keeping my fingers crossed that my fish will be okay.


I'll bet they are fine as long as you don't get one of those freak heavy wet snowstorms again after ice out! \:o

Out your way my respected mentor that produces yellow perch apparently has foregone the paddlewheel aerators for diffusers in his pond in the summer. He also doesn't crank up his diffuser in winter until he feels it's needed. I would assume he doesn't wait until D.O. get so low he would be bringing up anoxic water, but keeps an eye on it and when he thinks levels are falling he cranks it up and opens some water. Maybe if you have a D.O. meter that is a better approach?
Posted By: Cecil Baird1 Re: Winter aeration: Still Learning - 03/08/10 02:19 AM
 Originally Posted By: Todd3138
Wow, Cecil, sorry to see that much loss for you. Glad you had good numbers to start with though.

We hit 52 here today and had bright sunshine. The whole week is supposed to be really mild. I'm hoping I can make it out to our farm on Wednesday for the first time in approaching a month. There was ice when I was there last, but it wasn't terribly thick. I'll be interested to see if we lost any fish as the best pond, our small one, is really quite shallow across most of the pond with just one deeper area reaching probably 4 feet or so.


Heavy snow on ice for an extended period of time is when you need to worry. Apparently fish cages too close to the diffuser if you run one in winter is not good for larger fish either.

What's crazy is last winter I didn't use a diffuser and got concerned when pond D.O. levels dropped to 3.0 ppm, and may have fallen farther due to heavy snow cover. So I cut a hole in the ice and cranked up a massive surface aerator, which melted a hole in the ice at least 30 feet in diameter. I ran 24/7 for two weeks even in sub zero weather until the ice went out. I lost zero fish in the cages. Perhaps the two weeks wasn't enough to stress them? Or the fish were smaller? The aerator was really close to the cages too. Go figure.
Posted By: CJBS2003 Re: Winter aeration: Still Learning - 03/08/10 08:57 AM
Could some of the mortality particularly in the big BG just be natural? The % of fish that die in each year class has to go up each year from natural causes. You may have done less wrong than you think...
Posted By: Cecil Baird1 Re: Winter aeration: Still Learning - 03/09/10 01:17 AM
 Originally Posted By: CJBS2003
Could some of the mortality particularly in the big BG just be natural? The % of fish that die in each year class has to go up each year from natural causes. You may have done less wrong than you think...


Good point although they weren't very old. Ever notice in science there is rarely a clear cut cause and effect? There are always other possible factors or a combination of factors. I guess that's why when one does an experiment one has a control.
Posted By: adirondack pond Re: Winter aeration: Still Learning - 03/09/10 01:30 AM
 Originally Posted By: Cecil Baird1

Ever notice in science there is rarely a clear cut cause and effect? There are always other possible factors or a combination of factors.


Your right Cecil, it's always those unknown variables that end up biting us in the butt. ;\) sort of like global weather patterns.

PS. Howd you get that last photo?, did you have a camera on top of a pole.
Posted By: Cecil Baird1 Re: Winter aeration: Still Learning - 03/09/10 03:29 AM
 Originally Posted By: adirondack pond


Your right Cecil, it's always those unknown variables that end up biting us in the butt. ;\) sort of like global weather patterns.


Ummmm you said the 'G' word! \:o

 Originally Posted By: adirondack pond
PS. Howd you get that last photo?, did you have a camera on top of a pole.


No, just standing on the pier. It could be I zoomed in, which made it look like that.
Posted By: andedammen Re: Winter aeration: Still Learning - 03/09/10 07:09 AM
I 'm not shure you did any thing wrong.
http://snm.ku.dk/forskning/projekter/fiskeatlas/nyheder/2008032/
Link is observations reported to university of Copenhagen Denmark, and simmilar reports/observationes keep pooring in, no that the ice starts melting.
So whats differente? this year.
My unsientific thaugt unnormaly long time with ice/snow cover of ponds/lakes after a number off sucsesive yerars with high temp. no or little ice/snow (wich is the real abnormal in a longer time prospective).

mostely common roach,but also a number of perch, pike and crayfish are the spieces involved
These fish were not supercooled but has had ideal environemente to expand in, for years. Then mother earth does what she allways eventualy does, adjust populationes of differente speices.
This I observe whit the deers around here aswell, a number of good sucsesive years for them to grow, then one heavy winter and bang.
Maybe its do to areation???????????
But it might be youst a natural sving.

Posted By: Bill Cody Re: Winter aeration: Still Learning - 03/09/10 02:28 PM
Raising fish in a cage is not like raising them in open water. Fish in a cage are exposed to different and added stressors compared to the free swimming fish. The stressors change as the fish grow larger and the seasons change. All stressors almost always weaken or lower a fish's resistance making them more vulnerable to things that can more easily or more quickly lead to mortality. That is why when one has fish in a cage and they are valuable to you, it is important to regularly monitor their status and not ignore them and just assume everything is okay because none are floating.
Posted By: Cecil Baird1 Re: Winter aeration: Still Learning - 03/10/10 04:33 AM
 Originally Posted By: Bill Cody
That is why when one has fish in a cage and they are valuable to you, it is important to regularly monitor their status and not ignore them and just assume everything is okay because none are floating.


What was I supposed to do in the middle of winter, get them HBO and a beer now and then?

No options Bill. Couldn't move them and D.O. levels were good in the pond.
Posted By: esshup Re: Winter aeration: Still Learning - 03/10/10 04:49 AM
I'll bet you could have moved them, all you had to do is walk around on the ice a bit near the cages.....
Posted By: Cecil Baird1 Re: Winter aeration: Still Learning - 03/11/10 03:25 AM
 Originally Posted By: esshup
I'll bet you could have moved them, all you had to do is walk around on the ice a bit near the cages.....


Yeah I'm sure my falling in would have entertained them a little. You know how curious bluegills are.
Posted By: Todd3138 Re: Winter aeration: Still Learning - 03/12/10 12:50 AM
 Originally Posted By: Cecil Baird1


What was I supposed to do in the middle of winter, get them HBO and a beer now and then?


I know I'm new to pondmeistering and all, but, yeah, that seems like a pretty reasonable thing to do if you really gave a rat's rear end about the poor things!
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