Catcher, the demo fish had been frozen but was thawed out for the demo. It was further transformed into an alder-planked treat....MMM! MMM!







As FishMonger pointed out, the main advantage of doing it this way is to minimize wastage of hard earned meat! He is also correct in suggesting how exceptionally well it works on big fish, where the wastage factor can become HUGE. Here are some pic's of the technique being used on ungutted kings that I previously posted on an older thread about filleting big fish:

BEFORE:


AFTER:






And here's another one:
JUST GETTING STARTED: