The particular fish kill model I was suggesting indicates that the bottom temperature could have been far colder. Not from local air temperatures, as you have noted from experience that would be essentially impossible, but from much colder water being feed into the system from upstream.

It looks like the two likely compounding factors are an inability to escape to warmer [even a degree or two] water and the fact that large numbers of fish were massed together.
Another version of that could be that large schools massed together all tried to crowd into limited space in a thermal refuge and exhausted the DO.

The whole thing still feels weird to me, for one reason being I'm having trouble with the coincidence of the bird deaths.

I do like the idea that if it is the Rapture, I'll get my house and car back from my ex.

Thanks for the physics lesson.
I guess the past 40 years of catching fish through the ice of frozen ponds as I have done has defied science.

Like he indicated it's not the temperature itself that is necessarily the stressor it's the rapid temp change. You do know ice actually acts as an insulator and barrier and stabilizes temps under the ice albeit low temperatures right?

In pond management we have a term called "superchill" where someone attempting to prevent winterkill overdoes it on the diffuser aeration and chills the water column. This is due to the open water exposed to severe cold temps which can break up and drop the sanctuary temps that are in the upper 30's on the bottom. It takes a lot of energy and very cold temps but it can happen.

I did it the first winter of one of my ponds years ago and had all kinds of fungus problems with all of the fish in the sunfish family come spring which culminated into bacterial issues once the water warmed up.

My guess is in the Chesapeake Bay this happens more frequently when there is a large YOY age class that doesn't make it to deeper warmer water fast enough.

Edited by az9, 12 January 2011 - 09:34 PM.