Angling for the greenies can remove many of them. But I personally think the trapping is a better option to remove green sunfish. Here is why. Intensive fishing pressure on a small pond such as yours (0.5ac) will condition the overall fish community to become hook smart and you will have more difficulty in the future catching the resident fish. Traps are very effecive at catching greenies and they do not inpact the hook and line fishing prospects.

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management