Without a shocking survey, an exact answer to your question is not possible. A great number of other variables are present, including other fish species present, especially forage, other predator species, amount of available cover, etc. However, in 15 acres, you can likely remove every runner sized bass [6-12or14 inches] you and all your friends can possibly catch without any risk of seriously depopulating the bass. You'll know you're making progress when you start catching larger, fatter bass.
