passing the 15-year mark. Introduced species Grass carp have been introduced to many countries around the world. In the Northern Hemisphere, countries and territories of introduction include Japan, the Philippines, Malaysia, India, Pakistan, Iran, Israel, the United States, Mexico, Sweden, Denmark, the United Kingdom, France, Germany, the Netherlands, Switzerland, Italy, Poland, the Czech Republic, Slovakia, Romania, Croatia, Slovenia, Serbia, Montenegro, Bosnia and Herzegovina and Macedonia. In the Southern Hemisphere, they have been introduced to Argentina, Venezuela, Australia, New Zealand, Fiji and South Africa. Grass carp are known to have spawned and established self-reproducing populations in only six of the many larger Northern Hemisphere rivers into which they have been stocked. Their failure to establish populations in other rivers suggests they have quite specific reproductive requirements. In the United States, the species was first imported in 1963 from Taiwan and Malaysia to aquaculture facilities in Alabama and Arkansas. The first release is believed to have been an accidental escape in 1966 from the U.S. Fish and Wildlife Service's Fish Farming Experimental Station in Stuttgart, Arkansas, followed by planned introductions beginning in 1969. Subsequently, authorized, illegal and accidental introductions have been widespread; by the 1970s, the species had been introduced to 40 states, and it has since been reported in 45 of the country's 50 states. In 2013, it was determined to be reproducing in the Great Lakes Basin. It is still stocked in many states as an effective biocontrol for undesirable aquatic vegetation, many species of which are themselves introduced. Use Weed control Grass carp were introduced into New Zealand in 1966 to control the growth of aquatic plants. Unlike the other introduced fish brought to New Zealand, the potential value and impact of grass carp was investigated in secure facilities prior to their use in field trials. They are now approved by the New Zealand government for aquatic weed control, although each instance requires specific authorization. In the Netherlands, the species was also introduced in 1973 to control over-abundant aquatic weeds. The release was controlled and regulated by the Dutch Ministry of Agriculture, Nature, and Food Quality. In both of these countries, control is made easier because grass carp are very unlikely to naturally reproduce because of their very specific breeding requirements, but elsewhere, control is obtained by the use of sterile, triploid fish. Food Grass carp is one of the most common freshwater farmed fish in China, being one