The Deba is a single beveled blade (one side cambers and the other side is concave) meaning it can be a sharper knife than a double bevelled knife like most western knife.
The Deba is a short yet powerful knife which was originally used to slice tobacco exported to Portugal yet in became an all purpose knife most frequently used for heavy work on fish.
The Deba knife has a thick spine and can be used to chop, fillet and slice fish.
For those who haven't used it before it takes a little time to get used to (as with any single bevel knife) however once you get the knack your fish will be cleaner cut and prepared than ever before.
Given 85% of us live on the coast maybe one day we will all be wielding a Deba knife :)