Their diet was predominantly sardines, midshipmen, flatfish, rockfish, and squid. Examples of white fish are cod, haddock and flatfish. The Gulf flounder is a flatfish that swims on its side. The scale-eye plaice is a flatfish of the family Pleuronectidae. Flounders are a group of flatfish species. The Atlantic halibut is the world's largest flatfish. The Pacific halibut is the largest flatfish in the family Pleuronectidae. Cod and other gadids, flatfish, herring, wrasse and skates are also important locally. Many flatfish, such as flounders, have eyes placed asymmetrically in the adult fish. Benthic fish which can bury themselves include dragonets, flatfish and stingrays. Several flatfish which live on intertidal mudflats feed on the ragworm. Beam trawling is used in the flatfish fisheries in the North Sea. They are also used for baiting lobster pots and handlines for catching flatfish. In winter, it feeds on benthic prey, mostly flatfish, under dense pack ice. Pleuronectiformes (flatfish) are an order of ray-finned fish.