esshup,
Your results certainly do sound like an extraordinary amount of biomass for a small pond.
However, we are all used to ponds that have a "normal" distribution of fish sizes.
If the pond literally has zero reproduction of LMB, BG, and YP, then might all of the biomass be tied up in a few big fish and not as badly pushed against the impending crash line as we expect?
(I know that a few big fish would account from much more biomass than countless little fish. But how about a pond that essentially has zero "medium-sized" fish for each of the existing species?)
