Well, guest. you are not telling me that they still sell this stuff in the south?- surely not!! as for its name, it's certainly not a species of salmon, or you must have a vivid imagination.
It's some kind of Huss or dogfish, as I recall from my days in East Kent, so it is mis-named!
Not getting into a discussion about northern and southern fish suppers- there's only one winner there, and nothing to do with rock salmon