Set salmon down with the head end pointing right. Trim half an inch off of the head end and all of the salmon's fins. Insert
a sharp knife, horizontally, into the head-end, just above the
column of bones running down the middle of the fish. With your
knife angled downward, carefully cut along those bones
toward the tail, loosening the fillet from the bones. Now lift the fillet
up and very carefully cut it away from the rib cage and tail.