Sam,
First, welcome to Pond Boss. We should be able to answer a lot of your questions about the pond and pond management.
It really depends on the size of the channel cats, as to what they will do. Once they get large, maybe 24 inches long, they can become major predators of everything swimming in your pond. They will compete very heavily with your large mouth bass and they will eat your bass fry. But, that is not all bad in some cases. It really depends on the goal of your ponds management.
You mention that you have black crappie as well as numerous species of small panfish and minnows. Crappie can pretty easily get out of control, although a good population of large mouth bass can mostly keep them controlled. Similarly, if you have "undesireable" sunfish in your pond, the catfish and the bass will help clean them out.
If you can keep reasonable numbers of channel cats, maybe 15-20 per acre, that are less than 20 inches, they are great fun to catch and they are great to eat. But if those same fish get to 30 inches, you've got major trouble, because they will be extremely difficult to catch, they will muddy your pond, and they will eat everything in sight (or within touch of barbel).
Ken
