I jetski'd in the tailrace in April when I was 16. Old school stand up/kneel down type ski.... IDIOT. My brother has also scuba-dove there as well. He told me there are some scary huge sturgen and cats around the boulders. Not an area to be taken lightly doing anything, even shore fishing.
Yup, I don't know that I'd be nervous around any of the fish.. but getting conked on the head by a boulder, or maybe getting shoved into a crevice on the upstream side of a big rock.. it ain't for me. I've also seen upwellings of water, where the surface rises 6 or 8 inches - dramatically, temporarily.
It's not an "evil" place or anything. Just a place that pretty much requires paying attention and having some respect.
And yes, lifejackets are never a bad idea...