Whitefish (white fish, demersal fish) is a fisheries term referring to several species of oceanic deep water fish with fins, particularly cod (Gadus morhua), whiting (Merluccius bilinearis), and haddock (Melanogrammus aeglefinus), but also hake (Urophycis), pollock (Pollachius), or others. Unlike oily fish, white fish contain oils only in their liver, rather than in the gut, and can therefore be gutted as soon as they are caught, on board the ship. White fish has dry and white flesh. White fish are divided into round fish which live near the sea bed (cod, coley) and flatfish such as plaice which live on the sea bed. White fish is sometimes eaten straight but often used reconstituted for fishsticks, gefilte fish, lutefisk, surimi (imitation crabmeat), etc. For centuries it was preserved by drying as stockfish and clipfish and traded as a world commodity. It is most widely known as the key ingredient in the classic British dish fish and chips. In Jewish cuisine, smoked whitefish salad is a delicacy enjoyed with bagels.