It's a toothy giant that can grow longer than a horse and heavier than a refrigerator, a fearsome-looking prehistoric fish that plied U. Persecuted by anglers and deprived of places to spawn, the alligator gar—with a head that resembles an alligator and two rows of needlelike teeth—survived primarily in southern states in the tributaries of the Mississippi River and Gulf of Mexico after being declared extinct in several states farther north. To many, it was a freak, a "trash fish" that threatened sportfish, something to be exterminated.
The silver carp is a deep-bodied fish that is laterally compressed. They are a very silvery in colour when young and when they get older they fade from a greenish colour on the back to silver on the belly. These fish were introduced from Germany in to the Marble Hall experimental fish farm on the Olifants River.
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Several species of heavy-bodied cyprinid fishes are collectively known in the United States as Asian carp. Cyprinids from the Indian subcontinent—for example, catla Catla catla and mrigal Cirrhinus cirrhosus —are not included in this classification and are known collectively as "Indian carp". All the above, except largescale silver carp, have been cultivated in aquaculture in China for over 1, years.
Dear EarthTalk : What exactly are Asian carp, and why are they such a big problem lately? Introduced in the southeast to help control weeds and parasites in aquaculture operations, these fish soon spread up the Mississippi River system where they have been crowding out native fish populations not used to competing with such aggressive invaders. Asian carp are hardy, lay hundreds of thousands of eggs at a time and spread into new habitat quickly and easily.
For more information on the Invasive Species Act and Regulations visit www. Asian carps were brought from Asia to North America in the s and 70s. Since then they have migrated north through U.
Carp are a family of fish native to Europe and Asia. The common carp Cyprinus carpio has been in the US for over years. The newest carp invaders, bighead carpblack carpgrass carpand silver carp collectively known as "Asian carp"however, are causing their own brand of trouble in the Mississippi River and rivers and lakes within the Mississippi rivershed.
Asian carp are capable of surviving and growing in much larger portions of Lake Michigan than scientists previously believed and present a high risk of becoming established, according to a new modeling study from University of Michigan researchers and their colleagues. Some previous studies suggested that low food levels in Lake Michigan could be a barrier to the establishment of bighead and silver carp, which typically feed on algae and other types of plankton. Bighead and silver carp are the two Asian carp species of greatest concern for the Great Lakes. But earlier studies did not consider the fact that bighead and silver carp are opportunistic feeders capable of surviving on a wide variety of diets, including dead organic matter called detritus.
These carp are native to China. They were originally imported into the southern United States in the s to provide an inexpensive, fast-growing addition to fresh fish markets. They also served to help keep aquaculture facilities clean.