I didn't think we had bluecat in Stockton lake, so I e-mailed Dale Cornelius, the Fisheries Management Biologist for Cedar, Dade, and Polk counties and this was his response.
As far as I know there has never been a bluecat caught from Stockton Lake. But, I wouldn’t go as far as to say there are none. Bluecats were historically present in the Osage River watershed before the tributaries were impounded so it is a mystery to me (and others) why they have not shown up in Stockton or Pomme de Terre Lakes. I have be told by fairly reliable sources that bluecats have been caught in Pomme, but those were never verified by a biologist. Often anglers will mis-identify a large male channel catfish as being a bluecat because of their similar coloration.
Thanks for your interest!