| Silver carp | |
|---|---|
.jpg) | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cypriniformes |
| Suborder: | Cyprinoidei |
| Family: | Xenocyprididae |
| Genus: | Hypophthalmichthys |
| Species: | H. molitrix |
| Binomial name | |
| Hypophthalmichthys molitrix (Valenciennes, 1844) | |
| Synonyms | |
| |
.jpg)
Thesilver carp orsilverfin (Hypophthalmichthys molitrix) is a species offreshwatercyprinidfish, a variety ofAsian carp native toChina andeastern Siberia, from theAmur River drainage in the north to the Xi Jiang River drainage in the south.[3] Although athreatened species in its natural habitat, it has long beencultivated in China as one of the "Four Famous Domestic Fish" (四大家鱼) together withbighead carp,black carp andgrass carp.[4] By weight, more silver carp are produced worldwide inaquaculture than any other species of fish except for thegrass carp. Silver carp are usually farmed inpolyculture with otherAsian carp, or sometimes withcatla or other fish species.
The species has also beenintroduced, or spread by connected waterways, to at least 88 countries around the world. The reason for importation was generally for use in aquaculture, but enhancement ofwild fisheries andwater quality control have also been intended on occasion.[5] In some of these places, the species is consideredinvasive.[6][7][8]
The silver carp reaches a typical length of 60–100 cm (24–39 in) with a maximum length of 140 cm (55 in)[9] and weight of 50 kg (110 lb).[3]
The silver carp is afilter feeder, and possesses a specialized feeding apparatus capable of filtering particles as small as 4 μm. Thegill rakers are fused into a sponge-like filter, and an epibranchial organ secretes mucus, which assists in trapping small particles. A strongbuccal pump forces water through this filter. Silver carp, like allHypophthalmichthys species, have nostomachs; they are thought to feed more or less constantly, largely onphytoplankton, and also consumezooplankton anddetritus. In places where this plankton-feeding species has been introduced, they are thought tocompete with nativeplanktivorous fishes, which inNorth America includepaddlefish (Polyodon spathula),bigmouth buffalo (Ictiobus cyprinellus),gizzard shad (Dorosoma cepedianum), and young fish of almost all species.[10][11]
Because they feed onplankton, they are sometimes successfully used for controlling water quality, especially in the control of noxiousblue-green algae (cyanobacteria). Certain species of blue-green algae, notably the often toxicMicrocystis, can pass through the gut of silver carp unharmed, picking up nutrients in the process. Thus, in some cases, blue-greenalgae blooms have been exacerbated by silver carp, andMicrocystis has also been shown to produce more toxins in the presence of silver carp. These carp, which have natural defenses to their toxins, sometimes can contain enough algal toxins in their systems to become hazardous to eat.[10]
The silver carp in its natural rangemigrate upstreams forspawning;eggs andlarvae then drift downstream, and young fish hatch in thefloodplain zone. Larvae and small juveniles feed onzooplankton, switching tophytoplankton once a certain size is reached. The species is somewhat sensitive tolow oxygen conditions.[12]
The species is currently classified asnear threatened in its original range, as its habitat and reproductive behavior are impacted byconstruction of dams,pollution, andoverfishing. Population declines appear to have been particularly significant in the Chinese parts of its range.[1]
Silver carp are filter feeders, thus are difficult to catch on typicalhook-and-line gear. Special methods have been developed for these fish, the most important being the "suspension method", usually consisting of a largedough ball that disintegrates slowly, surrounded by a nest of tinyhooks embedded in thebait.[10] The entire apparatus is suspended below a large bobber. The fish feed on the small particles released from the dough ball and bump against the dough ball, with the intention of breaking off more small particles that can be filtered from the water, eventually becoming hooked on the tiny hooks.[citation needed]
In some areas, using "snagging gear", in which large weightedtreble hooks are jerked through the water, is legal to snag the fish. In the United States, silver carp are also popular targets forbowfishing; they are shot both in the water and in the air. In the latter case,powerboats are used to scare the fish and entice them to jump out of the water, and the fish are shot when they are airborne.[citation needed]
Two other species are in the genusHypophthalmichthys, thebighead carp (H. nobilis) and thelargescale silver carp (H. harmandi). The genus nameAristichthys has also sometimes been used for bighead carp, but is deprecated.[13] The bighead carp differs from the silver carp in its behavior (it does not leap from the water when startled) and also in its diet. Bighead carp are also filter feeders, but they filter larger particles than silver carp, and in general consume a greater proportion of zooplankton in their diets than silver carp, which consume more phytoplankton.[14] In at least some parts of theUnited States, bighead and silver carp hybridize in the wild and produce fertile offspring.[15]
The largescale silver carp is closely related to the silver carp, but its native range is to the south of that of the silver carp, mostly withinVietnam.[16] Unlike bighead and silver carp, largescale silver carp have not been widely introduced around the world for use in aquaculture, although at least one introduction was made to some waters of theSoviet Union, where they hybridized with the introduced silver carp.[17]
Silver carp were imported to North America in the 1970s to control algal growth inaquaculture and municipal wastewater treatment facilities, but escaped from captivity soon after their importation,[6] and are now considered a highlyinvasive species.[18]
Silver carp, with the closely related bighead carp, often reach extremely highpopulation densities, and are known to have undesirable effects on the localenvironments and native species, including thebigmouth buffalo.[8][19] They have spread into theMississippi,Illinois,Ohio,Missouri,Tennessee,Wabash Rivers, and many of their tributaries in the United States, and are abundant in theMississippi catchment fromLouisiana toSouth Dakota andIllinois.Dams seem to have slowed their advance up the Mississippi River, and until late November 2008, silver carp had not been captured north of centralIowa on the Mississippi.[20] Dams that do not havenavigation locks are complete barriers to natural upstream movement of silver carp, unless fishermen unintentionally assist this movement by the use of silver carp as bait.[6][21]
In 2020,Alabama Department of Conservation and Natural Resources found silver carp inAlabama'sPickwick andWheeler reservoirs on the Tennessee River, but the species has not expanded its range in Alabama's waterways.[21]
TheTennessee Valley Authority (TVA) has considered several methods to control the spread of Asian carp, including fish barriers at 10 locks controlled by the TVA. One is abioacousticsfish fence, which uses a combination ofsound, light andair bubbles. These barriers are installed atBarkley Lock and Dam inKentucky, and are currently being studied for their effectiveness in deterring Asian carp. Other types of barriers used for Asian carp includecarbon dioxide andelectricity. The TVA has conductedenvironmental impact studies to minimize the impact of the barriers on native species. The TVA has also considered adjustingflow rates during Asian carp spawning periods, which are usually during high-water events, as Asian carp eggs are only semibuoyant and will sink to the bottom and die with low river flow.[21]
The silver carp is sometimes called the "flying" carp for its tendency to leap from the water when startled; it can leap up to 10 ft (3.0 m) into the air.[22] Boaters traveling in uncovered high-speed watercraft have been reported to be injured by running into airborne fish while at speed. A leaping silver carp broke the jaw of a teenagerbeing pulled on an inner tube,[22] andwater skiing in areas where silver carp are present is extremely dangerous.[23] Peculiarly, the extreme jumping behavior appears to be unique to silver carp of North America; those in their native Asian range and introduced to other parts of the world are much less prone to jumping. Although theories have been proposed (for example, the high densities the species reaches in parts of North America, or that the introduced North American population may have been based on a small number of particularly "jumpy" individuals), the reason for these geographic differences is not known for certain.[24][25]
| Carp groups |
|  |
|---|---|---|
| True carp species |
| |
| Other carp species | ||
| Diseases | ||
| Recreational fishing | ||
| Carp anglers | ||
| As food | ||
| Related topics | ||
Principal commercialfishery species groups | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wild |
|  .png)  | ||||||||||||||||||
| Farmed | ||||||||||||||||||||
| International | |
|---|---|
| National | |
| Other | |
