Soliciting Aid to Remember Title & Author

I am desperately trying to remember the title and author of a marvelous novel I read in the late 1960s or perhaps early 70s. I recall that the author was a well-known American with a large following. My initial recollection was that it was Thornton Wilder, but I am becoming more and more unsure of that.

The plot was a simple one, yet beautifully told. It concerned a relatively young Scottish lad who caught a marvelous salmon in a Scottish river some considerable distance from his home. The story concerned the trials and tribulations he encountered attempting to bring his prized catch home. I can't recall, but suspect, that it was allegorical.

I would deeply appreciate any assistance in jogging my memory as I wish to purchase a copy from an out-of-print house. BTW, I further recall I received the book originally through the BOMC and that it was highly touted at the time.

Make the Scottish fisherman Cuban and the fish a marlin and it sounds like The Old Man and the Sea by Hemingway.