You may be right about ammonia. I understand a lot of chicken manure was put on the field. Plus cattle graze on it and have access to the pond. But the cattle have been a constant for 30 years.

The chicken manure came from local chicken houses. No telling what those chickens are fed and what is in the manure.

You may also be right about the BG being in the shallow water for spawning and thus be susceptible.

One other fact was my parents said the water seemed warmer than usual. I understand that warmer water holds less DO. The weather has been warm but nothing like it gets in the summer. Do you think the die-off of phytoplankton could also raise the water temperature?

There were hundreds of BG swarming around the springs. Maybe all the LMB are all gone and all we have left is a bunch of BG. No LMB or BG have been stocked since the original stocking done years ago.

Thanks for the input.