I agree with every thing Bob said but it sounds like you have a classic case of a bass heavy pond. The least expensive thing you can do is to have it fished often for bass. If all the bass are the sizes you said they all come out, you will never take out to many in that size range.
Next you start spending money, as Bob said fertilize and feed(the bream) for a 10 acre pond budget at least $1500.00 per year.
After that you can stock addition forage fish which with a mature pond can get very expensive.
bottom line if the guy is serious about the pond have a pro shock it.