Interesting! That really does sound like a case where the population (of blue catfish) got past that point where their population is eating more of their potential predators than the other predators are eating them — and the blue catfish population took off.
I know the bass anglers will disagree, but, as invasive species go, you could sure do a lot worse than blue or flathead catfish. In fact, I often wonder why catfish are not more often used as predator control in the central US, of species that are unwanted or tend to overpopulate and stunt, as bluegill and green sunfish and sometimes channel catfish) often do. This might be particularly effective in ponds which do not have (or have very limited) spawning & recruitment structure for catfish, as the populations would be pretty controllable. Hybrid channel-blue catfish are naturally sterile, and grow fastest of all, as their energy all goes into growth, rather than some of it to reproduction.
The one advantage of bass is their larger gape at a modest age: A 2 lb. largemouth bass can eat a lot bigger, say, green sunfish than can a 2 lb. catfish. But, blue catfish typically grow faster, and as they become adults and go after larger fish, their heads (and gape) become so large they are actually a threat to the harvestable (by humans for dinner) bluegill. So, if it was MY pond or lake to issue regs for, I’d limit harvest of catfish in sizes that consume whatever fish one is trying to hold populations down, but open it up for, say, the big catfish, if they were chowing down too many bluegill over 8” long.
Granted that bass are where the money is: $50k bass boats bring in a lot of tax revenue for the State fisheries departments. But, good golly, which is the more challenging struggle, a 7 lb. bass (moderately rare), or a 25 lb. blue catfish (not rare at all in waters where they do well - that’s barely an adult!)
(For a really epic struggle, you hook a 4”-5” bluegill while fishing for bluegill, and then B4 you get it reeled in, a big catfish grabs that and manages to get hooked — and you get to try not losing Mr. Catfish on your dinky bluegill rig with a #8 fine wire hook on the end... I’ve had that happen twice - once landing the large channel cat, with the down-on-his-luck & rather mangled bluegill still in the catfish’ mouth, and once getting the catfish just close enough to glimpse, before it ran again — to a downed branch.
There is quite a business on the lake of catfish guides taking people out for ‘lunkers’. We’re talking 60 lbs & up. When you get an 80# cat, they are a sight to behold! These guides release back the big fish after pictures.