Went into town for my weekend cup of coffee and, as is S.O.P., walked out onto the railroad bridge to fish-watch. I was watching an 8" smallmouth hover over a rock that was about 6" in diameter. He seemed very defensive of his rock. Some smaller fish would get close and he'd shoo them away and come back to hover over his rock. Then the rock came up for air. Turns out it was a soft-shelled turtle. I'd seen smallies hang out downstream of turtles and carp to feed on goodies that drift down, but this guy was right on the turtle. If it had been a sucker, I would have been sure that he was sucking on the turtle. But smallies aren't built for that.
I watched for quite some time and then crossed to the other side of the river. Sure enough, there was a 12" smallie hovering around a 12" soft-shell. Same thing. Very aggressive towards any fish that got near him. The turtle would move a foot or two, and the smallie would follow. He wasn't hanging downstream, but was right on top of the turtle. Not sure what I was watching, but it was interesting. Any theories?