Doc do you see or catch a bunch of 10-12in LMB ? Do you think most of the 250 cats are there , if so that is 300lbs per acre of predators ? Have you seen any indication of cat reproduction ? How much are you feeding (lbs per day) If you add in the LMB and Crappie you have a lot of predators per acre. They may have cropped down you breeding BG population to much.

The MSU material , which I often cite here , is good info but basic and in some respects out of date. The authors are good friends of mine and highly respected by me ( as good of fisheries folks and people as you will find). I will point out though that those recommendations (on taking out BG) are for a BG/LMB pond and for a balanced fishery. Neither of those fit your situation or goals.

Buy a cheap fish trap from Wal-Mart and bait it with bread or dog food or fish food in a mesh bag and put it out. That plus seining are good ways to survey small BG populations.

There is great uncertainty here (lots of good info see - Crappie Pond http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=5;t=000461 ) on crappie in ponds. My guess is if you want crappie the pond must focus on them and don't expect good LMB or BG populations. The MSU book discourages crappie use in ponds.

Better start with what your goals are because in a pond it is hard to have it all unless you are going to have a put and take fishery using stockings of adult fish.

We can help walk you through the population assessment process hear if you like.