Thanks for the replies! I guess I should have provided more information, initially. In the past, the pond produced sufficient catches on small soft plastic jigs. I could go out for an hour or 2 and catch 30-40 fish (male bluegill were returned, bass over ~13-14" removed, and returned some crappie if I didn't feel like cleaning them). When fishing this earlier spring, I couldn't catch anything on the jigs, so I tried worms. They didn't provide acceptable results, either. I don't have specific catches per unit time, but I was fishing for an hour before losing interest, and only catch 1 or 2 bluegill. Then, this past Thursday afternoon/evening I set out to fish the entire pond (spread around in 3 dimensions) in the boat with live minnows. 5.5 hours of continual fishing produced 3 bluegill, and 1 LMB ~13". These are the results that triggered my quest for sampling the pond to determine what is there.
The pond is visible from my house, and I really don't think there has been any prowling fishermen. My neighbor's house is only about 60 yards from the pond, and he's never seen anyone there, either. He is the one who clued me in on the otter info. He has permission to fish, but rarely does.
