You need a natural resources attorney. What they are saying is not correct but is an attempt to scare you off.
That is exactly where I would go. None of this seems to make sense.
I don't normally suggest contacting Bob Lusk or Mike Otto at Pond Boss headquarters since they are so busy, but a call to the main office may get you some of the answers you need.
Possibly one of them will see this and provide some guidance.
Also -- the suggestion of a number of smaller ponds is excellent. It would give you several specialized ponds that would be easier to manage, and it would provide much more diversity than one big pond.
