Gambusia will not likely survive in your pond overwinter if the pond develops ice and has LMB.
Bill, this is strictly a smallie pond. If a largemouth ever ends up in my pound I'm putting a $100 bounty on it lol.
I figure that its a lot easier to manage a trophy smallmouth pond in New Jersey than a trophy largemouth pond. I only want to worry about harvesting bass. I don't need to be harvesting bluegills and other stuff too. If the pond gets overloaded with forage I'm sure I won't have any problems dealing with that lol.
Some minnow traps, a couple slices of bread, and a few hours of free time. If my shiners were overpopulating I could pull a few hundred out at a time, clip their tail fins, and toss them back in. My guess is that bass would make short work of them.