I’d bet 100:1 it is genetics and not trauma. I’d imagine any injury that would bend them up like that would be lethal. Plus, sounds like there is a lot of them out there. That’s a lot of fish escaping mortality from a event like that.
Anyway, I as I read the replies, I became more curious if there might actually be some advantage for a fish with this mutation. I can’t imagine it would be anything but a detriment, but then I wonder why so many are being caught.