I suggest you go through this link and read the threads listed. That will give you a good understanding of how crappie work in ponds.

http://www.pondboss.com/forums/ubbthread...ite_id=1#import

Many here like crappie but understand just how hard it is to manage them in a pond vs. a big lake (100 acre +).

I would want to understand your pond and goals very well before I hazard a guess as to what you should do to improve or change it. Especially given the results you have stated above.