Black carp

The black carp (Mylopharyngodon piceus) or black Chinese roach is a species of cyprinid fish and the sole species of the genus Mylopharyngodon. It is native to lakes and rivers in East Asia, ranging from the Amur Basin, through China, to Vietnam. It is widely cultivated for food and Chinese medicine. The black carp can reach up to 1.8 m (5.9 ft) in length and 35 kg (77 lb) in weight. It generally feeds on snails and mussels. The average length is 60–120 cm (23.5–47 in). Black carp, together with bighead, silver, and grass carps, make up the culturally important 'four famous domestic fishes' used in polyculture in China for over a thousand years, and known as 'Asian carp' in the United States. Black carp are not as widely distributed worldwide as the other three. In China, black carp are the most highly esteemed and expensive foodfish among the four domestic fishes, and partly because of its diet and limited food supply, is the most scarce and expensive in the marketplace. The nature of the black carp's diet has led to its use in the United States in the control of snails in aquaculture. Snails are obligate alternate hosts of trematode pests that can cause substantial losses to aquaculture crops. Some state aquaculture laws require the carp to be bred as triploids, to render them sterile, thus minimizing the potential for the fish to escape and create self-sustaining populations. However, the use of triploids does require the maintenance and use of fertile diploid brood stock at least at some location, for production of the triploids. No state allows the intentional release of black carp, sterile or otherwise. However, the United States Geological Survey reports that more than 60 confirmed black carp have been caught in the Mississippi River basin. Rivers where black carp have been captured also include the White in Arkansas, the Atchafalaya and Red in Louisiana, and the Kaskaskia and Illinois Rivers in Illinois. One confirmed escape of black carp from aquaculture has occurred on the Osage River in Missouri, but other escapes are likely, because most early captures were far from this location, in the southern Mississippi basin. Most of the captured fish have been confirmed to be diploid and assumed fertile. Two diploid fingerlings were captured in Missouri's boot heel in 2015, confirming natural reproduction of this species in the wild. In Louisiana, many other reports by knowledgeable fishers of their capture have not been verified by biologists. Black carp are considered to be a serious threat to mollusks native to the United States, many of which are critically endangered. In 2007, the black carp was listed as an 'injurious species' under the Lacey Act. It is thus illegal in most cases to transport live black carp, whether sterile or fertile, into the United States or across state lines. In states where legal, black carp can still be possessed.