Ginger produced in India is most often farmed through homestead farming. In coastal British Columbia, Fraser River white sturgeon are sustainably farmed to produce caviar. Chickens farmed for meat are called broilers. Chickens farmed primarily for eggs are called layer hens. When in use as livestock, the domestic pig is mostly farmed for its meat, pork. Contaminants are commonly found in the flesh of farmed and wild salmon. Salmon are intensively farmed in many parts of the world. Tilapia were originally farmed in their native Africa and Levant. Oyster depuration begins after the harvest of oysters from farmed locations. North Devon cattle are also farmed in the area. Rainbow trout are commercially farmed in many countries throughout the world. Ballarat West Town Common is presently farmed on by licensed farmers. The industry suffers problems due to fluctuating demand for farmed fish. CP Foods produces and sells farmed shrimp. The Mekong delta in Vietnam is farmed intensively and has little natural vegetation left.