Jake,

Your question sounds very similar to a previous question you had about a 5 acre pond in this post:

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000110

The advice given then by several folks was to remove as many of the undesirable fish as possible. Doing that will help improve your forage base for the LMB. In addition, it sounds like you also need to remove the small LMB, i.e LMB under 12 inches. By taking these steps, you will increase the available forage for the remaining LMB and improve their weights.

If the pond is 8 acres, you've got some fishing to do.