George,
I know that some hybrid blue x channel catfish were stocked over ten years ago. I didn't think many had survived the draining of the pond in 2003. I didn't count rays in the fins but the top two looked like those hybrids to me. Jeff from SE Pond and I have talked often about these large fish and what possible role they may play. Our only guess is that they could be controlling the large gizzard shad. We never have electrofished a shad over 10-12". We've decided not to remove the large fish because I do think that they are playing a role in our pond. I'd much rather remove more smaller catfish that compete with HSB and LMB for the same size forage item.
