I always filleted my fish from the top down like that salmon commercial guy is doing. Not as fast mind you, but over the top of the rib cage, not through it. I've always liked my Gerber knife for that with a little wider blade and more of a curve toward the tip. We charter fished on Lake Michigan, so I got to clean a lot of salmon and trout. In Canada I got the fish cleaning chore as well and all the northern went back into the lake. Smelly, bony things that they are.
Funny story. I was down in the fish cleaning house with another guy who was cleaning fish when the camp owner came in and read the guy the riot act for cleaning a fish with the knife pointed back toward himself. The guy looked kind of sheepish and said that it always worked okay back home at work. The camp owner asked him what kind of job was that? The guy said, "I'm a medical pathologist in Denver."
Camp owner, "Oh" quick exit.
He must have figured that the guy knew how to work a knife.
