I'm sorry to disagree with you but many, many pond never had fish. Where I
live there are ponds all over the place that never, ever had a fish. They
are there to water livestock.

"gene" wrote in message
oups.com...
The ponds that have fish in the wild are the ones whose fish didn't
die. The ponds that don't have fish are the ones whose fish did die. If
you could replicate the first, you would be fine, but how can you know
that you are not replicating the second?