Minimum D.O bluegill in cold water?

Anyone know what minimum D.O. in coldwater under the ice is for bluegills? Minimum for mortality and minimum for stress? Is it different than warmer temps? I'm seeing numbers all over the place on the Internet like 5 ppm to 4 ppm to 3 ppm.

I just caught D.O. levels in my 3/4 acre as low as 3.5 ppm with the meter and 4.75 ppm with a manual chem test in an open hole I made with the auger that was open for about an hour. I am opening up the pond with surface aerator 30 X 30 feet so far and all of my perch except one in a couple of floating cages have survived. I hope to get into the bluegill cage and take a peek tomorrow. The lid was frozen down to the ice so I couldn't see if I had survivors. I do know bluegill are more sensitive to low D.O. than yellow perch. If the bluegills survived I am cautiously optimistic for the free swimming bluegills.

I'm worried I may be too late as the aerator is giving off an odor which could be hydrogen sulfide. I should have installed a bottom diffuser in shallow water but thought keeping snow of the ice was good enough. Apparently not and I wasn't able to take snow off the ice for a couple of weeks as the ice was thin and had water under the snow.

Live and learn. I hope I didn't lose my bluegills as this will put me back a few years on my goals.

I don't know what the specific numbers are, but in general fish will have lower oxygen demand in cold water, and so can tolerate lower DO.

I believe sunfish require less DO than do yellow perch, so if your perch are alive I would think your bluegills would be as well. I am pretty sure that most sunfish species can tolerate DO levels down near 3ppm in warm weather for short time periods and would suspect it to be even lower in cold water. The smell you are noticing may be from the bottom of the pond, the aerator may actually be mixing up some decaying matter from the bottom of the pond.

I believe sunfish require less DO than do yellow perch, so if your perch are alive I would think your bluegills would be as well. I am pretty sure that most sunfish species can tolerate DO levels down near 3ppm in warm weather for short time periods and would suspect it to be even lower in cold water. The smell you are noticing may be from the bottom of the pond, the aerator may actually be mixing up some decaying matter from the bottom of the pond.

Thanks for you comments from both of you. I was able to remove the lid on the bluegill floating cage and there is no morbidity or mortality. I'm optimistic the rest of the pond should survive.

Actually Brian according to all the literature I found yellow perch are supposed to be pretty hardy when it comes to D.O. with bluegills and bass in the mid range. Crappies are supposed to be pretty hardy too. Bullhead and carp are apparently the hardiest. However I was not able to find any consistent cut offs for bluegills. I was told by Dr. Willis of South Dakota State that as long as my D.O. doesn't go below 3.0 I should be O.k. Apparently he's right.

It makes sense they should be more tolerant in cold water as their metabolism is slower.

Thanks!