pray tell.. wiki doesn't tell me a thing about this..
On Salem's nickname? Remember Salem (not the ship lol) was famous for that Witch Trial that decked several suspected of heresy and witchcraft. Its actually quite fitting for the Des Moines USS Salem to be nicknamed the "Sea Witch" or "Witch of the Sea" because of that history.
Also, strangely, the Des Moines sisters had interesting nicknames and radio callsigns:
Des Moines - Daisy May/Mae, Dizzy D, Crusader Salem - Sea Witch Newport News - The News, Thunder, The Grey Ghost of the East (interestingly enough, the ship that earned the Grey Ghost nickname should have been CV-6 Enterprise but she's usually called "The Grey Lady"
