Dwight --
Norm Kopecky has a multiple, multiple species pond to the southwest of Sioux Falls. He does a lot of feeding, and a lot of fish purchase and transfer to get his diversity. He has a wonderful set-up and has group after group of disadvantaged kids, adults, etc., fishing his pond. He has a covered bridge over part of the pond, and people can fish from there. In fact, vans can drive right to the edge of the bridge, and safely unload wheelchairs, etc. Norm uses circle hooks on all his rods, so the catching is easy, and the releases are successful as well.
I helped a landowner out near Gettysburg plan structure for his pond a couple of years back. We did just what you did -- ran a line of trees from shallow to deep water. It's a good plan.
It's pretty common for the carp not to successfully reproduce and survive in a sand/gravel pit type of pond. A few adults won't cause you problems, although at higher densities they will actually keep down the submergent plant growth through their rooting activities. As you can tell from Steve's post above, that could either be good or bad, depending on whether you have too much or too little vegetation. It's always something.
I wonder if your native vegetation has already had plenty of opportunity to establish, and you may already have the appropriate submergent plants?
Nice that I could use my 500th post on a northern pond!!
