Sharks appeared around 450 million years ago during the Devonian era. Consumption of shark meat has been recorded in literature as early as the fourth century. Persians and Cretans caught and sold sharks some 5 000 years ago in the Persian Gulf and the Mediterranean.
Sharks are a valuable resource. They posses a primary importance in some regions of the world, sustaining important fisheries in some countries. Moreover, they have been, and are, a cheap source of protein for coastal communities dependent on subsistence fisheries. Sharks provide many products that are used by humans. They are exploited for their meat (fresh, frozen, salted or in brine, smoked), fins (one of the most expensive fishery product, used to produce the famous shark fin soup), liver-oil (for cosmetics and pharmaceutics), skin (for leather and sandpaper), teeth (in jewellery), and, more recently, cartilage (ground to powder and proposed as an anti-cancer cure).