Anthropic, you talking about this bad boy? In 2014, I found this one in my hatchery pond. We've also seen smaller ones regurgitated by LMB during electroshockings. I never even thought about rearing them. My guesstimate is that the one in this pic was 8-10".
Yeah, Al, I think that's the same critter. We would hear them when they swam to the surface, released a breath "cusshhhh" (or maybe took a breath?), then went back down. Not sure they really needed to do that, but it was pretty common. Lake Jackson in Tallahassee, Florida back in the 60s.
I kinda wonder if they were part of the reason Lake Jackson was, for a time, the center of the trophy bass universe. Lots of meat on a large siren, and I'll bet they are easier for LMB to catch & swallow than a BG.