Firstly - I question the efficiency and percision of a dredging to 14 ft that occurred 20 yrs ago esp if it was done when the pond had water in it. Did Longhorn or anyone else measure the pond depths to produce a contour map after the dredging operation? 7 ft of accumulation is a whole lot of muck in 20 yrs (84in/20yr=4.2in per yr) but it is possible if lots of leaves and vegetation growth are deposited each year. Longhorn what is the typical annual weed-algae-tree leaf problem that gets deposited into the pond each year?
Secondly - Since it is a public pond there is undoubtedly a lot of greedy and unwise fish removal by anglers. Don't count on stocked fish to stay in the pond very long. Our local sportsmen club constantly has the pond raped by anglers-members. If this were not true a few bass 50-80 would be able to control the actual recruitment of Hy BG. Thus I as others highly suspect contamination from other more proflic sunfishes. I IL can keep the LMB in the pond long enough they should be able to get the small sunfish under control. IL - remember that a bass eats a sunfish about 1/3 the length of the bass. So if majority of your sufish problem is 4"-5" long then the size of bass you are stocking are too small to quickly reduce the overpopulation of "your" sunfish. Will the small bass stay in the pond long enough to grow to 13"-14" long?
Old catfish in a heavily fished pond can get conditioned to avoid most average anglers. Thus the larger ones may help in controlling small fish.
Thirdly - I agree with Dr Dave about the winter ice cover problem. Ice-snow cover in central IL should not be a big concern compared to the BOD (biological oxygen demand) problem.
