Hamish's views and mine are very much the same here.......but we'll probably have to agree to differ over the need for an angler in possession of a salmon permit, to carry a separate permit from the riparian owner if he wishes to fish for or take brown trout.
Sheriff Scott Robinson's bible on Scottish game law and (to a lesser extent) Lord Jauncey's wee booklet on fish poaching (both sadly out of print), each makes the point that when fishing for brown trout in waters also containing migratory fish, the Salmon Act applies.
As a quick example, here at Stoney the salmon rights on a stretch of the Cowie where it flows through Ury Estate belong to a separate estate proprietor and the brown trout rights to the immediate landowner. Under their salmon permits, Stoney AA members can fish there for salmon, seatrout and brown trout, but we can't (and wouldn't) try to stop folk properly authorised by the riparian estate owner, fishing alongside us for brown trout. If, that is, there were keepable brownies there to catch!
Which might lead on to a discussion on where "sea trout" really figure in this equation in terms of modern research by Andy Walker and Co.........let's please not open that particular can of worms!
Incidentally, the terms "superior" and "inferior" are nae mine (I rank all three fish as equal). They're simply legalistic terms. eg a right of salmon netting is superior to the inferior rod fishings which come with the netting right(see 'Royal Inverbervie Salmon' thread).