Originally Posted By: ewest
They could have been dead and under the ice for a while. I doubt it is the freeze thaw - freeze thaw but rather just to cold for to long. That is not a loss of fat supplies but just to cold.

I expect they were dead for some time before the thaws. The last two freeze-thaws (can't remember about the first) were preceded by bad supercooling events, 1-2 days of temps below 32 deg and high winds that mixed and cooled the pond but did not let it freeze quickly

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