How to make a nice salmon fillet.
Step 1: Tools
In these pictures, you will see several ulu knives, a fillet knife, a steel and a wrapped half salmon. An ulu is an Eskimo knife that is the perfect tool for the job. These knives, made by Chase Hensel, are Yup'ik-style, from Western Alaska, where salmon is the staple food (an ulu also does a bang up job cutting frozen meats and fish but these instructions are for a fresh or fully thawed salmon). These ulu blades are made from segments of a thick old cross cut saw blade, which is especially good for this purpose. The handles are ivory and wood. Choose the size of your ulu in proportion to the size of your fish. While we prefer to use an ulu, people also use fillet knives. In either case, you will need a sharp and rust-free blade. Use the steel frequently to keep your edge uniform.
Step 2: Wash the Fish
Rinse off any blood or slime on your fish. Clean the body cavity under running water. Pat the fish dry, inside and out, with paper towels (or you can use a clean rag or cotton dish towel, if you don't mind getting it fishy).
Step 3: Cut Out the Fins
With the tip of your knife, or edge of the ulu, cut out the dorsal and/or ventral fins, depending on whether you have a whole salmon or a half. Angle the blade slightly down and cut along the base of the fin, just far enough in to where the bones of the fin extend. Do this on one side of the fish. Then flip it over and cut out the other side in the same way.
Step 4: Fillet the First Side
With the flat of one hand, steady the salmon while you cut with the knife hand. Make an initial cut about one half to one inch deep along the length of the backbone to penetrate the skin and establish your line. With practice, you will be able to feel how deeply and evenly your knife is cutting. Then, starting at the head end, begin to slide your knife more deeply along the backbone, heading towards the fish's ventral side. That is, cut from the spine towards the body cavity with your knife at a shallow angle to the cutting board. As you move down the ribs, gently lift up the fillet and progressively work your way down the fish. Be careful not to press your thumb or fingers into the flesh or you will bruise it. To end up with a nice smooth fillet, there are two other things to watch out for. First, as you lift the meat off the bone, be careful not to bend the fillet too far back or the flesh will tear. Second, use smooth, long, even knife strokes, all in the same direction. Do not use a sawing motion or you will end up with a ragged fillet. As you work, think of the knife as pressing along the backbone as it separates the meat from the bone. This requires a bit of downward pressure, a slight angle to the knife, and a feeling for the resistance of the ribs, which is different than the resistance of the flesh. If you get it just right, the ulu blade will ripple along the ribs like a scale down a piano and you can feel it riding over them. You want to leave as little meat on the skeleton as possible. When you have the fillet fully detached from the skeleton, cut the skin along the stomach with a vertical knife cut to completely free the fillet.
Step 5: Clean Your Knife and Sharpen It
Before proceeding to the other side of the fish, wipe off your knife blade and give it a few strokes with the steel.
Step 6: Fillet the Second Side
Set the first fillet to off the side. Turn the fish skin side up onto its exposed backbone. Wipe the skin with a paper towel. Cut into the fish just above the backbone, and then proceed as with the first fillet. If necessary, trim any unsightly bits off edges. Admire your beautiful fillets and make a fabulous meal!