Crappie are always a sensitive subject here, it all depends on your goals. Black crappie will always have a place my ponds, they are not that hard to manage if you pay attention and manage your pond correctly. You must be doing something right to have monster crappie, good job, but you can NOT stay on catch & release if you want larger bass...get Lusk's book, it has everything you need inside. Your predators need to be thinned and by the age of your pond, you probably need to harvest some of each size, including some of the oldest fish.