|
The bighead carp (''Hypophthalmichthys nobilis'') is a freshwater fish, one of several Asian carps. It has a large, scaleless head, a large mouth, and eyes located very low on the head. Adults usually have a mottled silver-gray coloration. This is a very large species, with a record size of 77.5 kg (170 lb) and a total length of 150 cm (59 in). But most places in the Mississippi River basin, a fish over 40 lb (18 kg) and 43 inches (110 cm) is considered very large. The average length is 24-32 inches (60-82 cm). Bighead carp are popular quarry for bowfishers; the (bowfishing record ), captured in the Mississippi River near Alton, Illinois, in May 2008, is 92.5 lb (42 kg). Bighead carp are native to the large rivers and associated floodplain lakes of eastern Asia. Their range extends from southern China to the Amur River system, which forms the northern border of China and the southern border of Russia.〔 They have been introduced widely outside their native range, where they are often considered invasive. The bighead carp has a tremendous growth rate, making it a lucrative aquaculture fish. Bighead carp, (unlike the common carp, with which Europeans and most North Americans are more familiar), are primarily filter feeders. They are preferentially consumers of zooplankton, but also consume phytoplankton and detritus. ==Bighead carp as invasive species== Its value as a food fish has caused it to be exported from its native China to more than 70 other countries, where it has invariably escaped or been intentionally released to the wild. Today, the bighead carp can be found in the wild in Europe, South America, and North America. It also has been introduced into most of the Indian subcontinent (India, Pakistan, and most Southeast Asian countries) and to lakes in western China to which it is not native. Bighead carp are not always considered undesirable, invasive species where they are introduced outside their native range, and they continue to be stocked in some water bodies to support commercial fisheries. Stocking bighead carp or silver carp usually increases the total biomass of fish available for harvest, but can decrease the catch of native and sometimes more valuable fish.〔 Bighead carp are considered a highly destructive invasive species in the United States. Bighead carp and the closely related silver carp (''H. molitrix'') were imported to the United States to remove excess or undesirable plankton, thus improve water quality in sewage treatment plants and aquaculture facilities. However, some fish escaped into the Mississippi River basin, where they are now firmly established. A (national plan for the control of Asian carps ), including bighead carp, was finalized in late 2007. In the United States, a limited market has developed for bighead carp, particularly in ethnic communities, and they are farmed in ponds for this purpose. The live or very freshly killed market is most lucrative. Because of this, bighead carp are often transported live, and may be a high risk factor for the eventual spread of the fish, either through release by the end purchaser, or through escape during transport. Another potential avenue for unintentional spread of bighead carp is through use as fishing bait.〔(Kolar et al. 2005. Asian Carps of the Genus Hypophthalmichthys (Pisces, Cyprinidae) ― A Biological Synopsis and Environmental Risk Assessment )〕 Communities are attempting to contain the spread of the extremely invasive bighead carp. New York has banned the import and possession of live bighead carp, with the exception of New York City, where they still may be legally sold in live food markets (but they must be killed before they leave the premises). Possession of live bighead carp has been illegal in Illinois since 2005. Since February 2007, using bighead carp as fishing bait has been illegal in Missouri. In December 2010, the U.S. Congress banned the importation of bighead carp.〔18 USCS § 42〕 Live bighead carp are also banned from sale in Canada. Several Greater Toronto Area Asian supermarkets have been fined in the past for selling them.〔http://www.thestar.com/news/gta/article/751564--invasion-of-the-bighead-carp-has-ontario-scared〕 The Ontario Ministry of Natural Resources banned the live sale and importation into Ontario in 2004. Fines are only CAD$3500.00 and have done little to deter the possession of this fish; underground selling continues to happen in several Chinese supermarkets in the region. One live carp was found in Toronto's Don River in 2003.〔http://www.insidetoronto.com/news/local/article/543719--supermarket-charged-for-carrying-live-bighead-carp〕 Killed carp can still be sold in stores, but Asian retailers and consumers prefer live over killed fish. Killed carp is cut into pieces: head, fillet, and tail. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bighead carp」の詳細全文を読む スポンサード リンク
|