Asian Carp
    
    
      
       
 Hypophthalmichthys molitrix  (Valenciennes in Cuvier and Valenciennes, 1844) | 
 
    
Common name: silver carp
Identification: Distinguishing
 characteristics were given in Berg (1949). Keys that include this 
species and photographs or illustrations are provided in several of the 
more recently published state and regional fish books (e.g., Robison and
 Buchanan 1988; Etnier and Starnes 1993; Pflieger 1997).
Size: 1 m and 27 kg.
Native Range: Several
 major Pacific drainages in eastern Asia from the Amur River of far 
eastern Russia south through much of eastern half of China to Pearl 
River, possibly including northern Vietnam (Berg 1949; Li and Fang 
1990).
 
 
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Alaska
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Hawaii
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Puerto Rico &Virgin Islands 
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Interactive maps: Point Distribution Maps
     Nonindigenous Occurrences:
     This
 species has been recorded from the Black Warrior and Tallapoosa river 
drainages of the Mobile Basin, including Yates Reservoir and throughout 
the central part of Alabama (Mettee et al. 1996; J. Hornsby and M. Pierson, personal communication; Rasmussen 1998); and from the Arkansas
 and White River systems (including the the lower Cache River), the 
Ouachita River, Bayou Meto Drainage, and the Mississippi River mainstem 
in Arkansas (Freeze and Henderson 1982; Carter and Beadles 1983; 
Courtenay et al. 1984; Robison and Buchanan 1988). It has been stocked 
in water treatment ponds on the East Slope of Colorado
 (D. Horak, personal communication).  A specimen was collected in power 
plant reservoir in Larimer Co.; plant is on Rawhide Creek; a trib of the
 Cache la Poudre River (Walker, unpublished).  It has been intentionally
 released in Hawaii (Davidson et al. 1992). It has also been collected or reported from several water bodies in, or bordering, Illinois,
 including the Mississippi, Spoon, Illinois, and Ohio rivers and several
 of their tributaries, the Muddy River, Muscooten Bay, Horseshoe Lake 
and vicinity in the Cache River drainage (Burr 1991; Burr et al. 1996; 
Laird and Page 1996; Illinois Natural History Survey2004; Hoff, pers. 
comm.; Etnier, pers. comm.; Thomas, pers. comm.; Irons, pers. comm.; 
Southern Illinois University, unpublished) and the Embarras River below 
Lake Charleston (K. Cummings, personal communication). There are also 
records of this species from the southeastern part of Indiana
 (presumably the Ohio River) (Courtenay et al. 1991; Simon et al. 1992) 
and west fork of the White River in Greene County (Anonymous 2003); the 
Des Moines and Chariton Rivers, Iowa (Iowa DNR 2003), White River at Hazelton (Caskey, pers. comm.) and the Wabash River (Thomas, pers. comm.); eastern rivers in Kansas
 and some unspecified location(s) in Kansas (Rasmussen 1998; Courtenay 
et al. 1991) (possibly the Missouri River); from the Ohio River, Clarks 
River, and non-specific locations in Kentucky
 (Pearson and Krumholz 1984; Burr and Warren 1986; Rasmussen 1998; 
Thomas, pers. comm.; Henley, pers. comm.; Southern Illinois University; 
Baxter, pers. comm.); from the lower Mississippi River and many 
tributary sites in Louisiana 
including the Atchafalaya, Red, Boeuf, Old, Ouachita, and Little river 
drainages, LaFourche Canal, Miller Lake, and Loggy Bayou (Freeze and 
Henderson 1982; Carp Task Force 1989; Douglas et al. 1996; Rasmussen 
1998; F. Bryan and J. Hughes Little, pers. comm.); the Mississippi 
River, Yazoo River, and Chotard Lake in Mississippi
 (Mississippi Museum of Natural Science 2004; Schramm et al. 2004); 
 from the Mississippi and Missouri river mainstems and the Lamine and 
Castor Rivers, Missouri 
(Courtenay et al. 1991; Robinson 1995; Pflieger 1997; Rasmussen 1998; 
Lien 2003), the Little River Ditches, Upper Mississippi-Cape Girardeau, 
and The Sny drainages (Southern Illinois University), the Lower 
Missouri-Moreau, Lower Grand, Lamine, Lower Osage drainages (Chapman, 
pers. comm.); the Missouri River drainage and Elkhorn River Nebraska
 (Nebraska Game and Parks 2000) and established in Boyer Chute National 
Wildlife Refuge (USFWS 2005); the Missouri River up to Gavins Point Dam 
(W. Stancill, pers. comm.), the Big Sioux River near Canton (T. St. 
Sauver, pers. comm.), and the mouth of the James River (R. Klumb, pers. 
comm.) in South Dakota. They also have been collected from a Mississippi River outflow in Tennessee (C. Saylor, personal communication; Etnier, pers. comm.) and McKellar Lake in Memphis (Baxter, pers. comm.).
   
   This species has also been collected at golf course ponds at Dorado Beach Hotel in Puerto Rico (Erdman 1984).
    
    
Means of Introduction: This
 species was imported and stocked for phytoplankton control in eutrophic
 water bodies and also apparently as a food fish. It was first brought 
into the United States in 1973 when a private fish farmer imported 
silver carp into Arkansas (Freeze and Henderson 1982). By the mid 1970s 
the silver carp was being raised at six state, federal, and private 
facilities, and by the late 1970s it had been stocked in several 
municipal sewage lagoons (Robison and Buchanan 1988). By 1980 the 
species was discovered in natural waters, probably a result of escapes 
from fish hatcheries and other types of aquaculture facilities (Freeze 
and Henderson 1982). The occurrence of silver carp in the Ouachita River
 of the Red River system in Louisiana was likely the result of an escape
 from an aquaculture facility upstream in Arkansas (Freeze and Henderson
 1982). The Florida introduction was probably a result of stock 
contamination, a silver carp having been inadvertently released with a 
stock of grass carp being used for aquatic plant control (Middlemas 
1994). In a similar case, the species was apparently introduced 
accidentally to an Arizona lake as part of an intentional, albeit 
illegal, stock of diploid grass carp (W. Silvey, personal 
communication). Pearson and Krumholz (1984) suggested that individuals 
taken from the Ohio River may have come from plantings in local ponds or
 entered the Ohio River from populations originally introduced in 
Arkansas.
Status: Records
 are available for 12 states. It is apparently established in Louisiana 
(Douglas et al. 1996) and is possibly established in Illinois; silver 
carp have been reported in Alabama, Arizona, Arkansas, Colorado, 
Florida, Indiana, Kansas, Kentucky, Missouri, and Tennessee. Douglas et 
al. (1996) collected more than 1600 larvae of this genus from a 
backwater outlet of the Black River in Louisiana in 1994. Burr et al. 
(1996) found young-of-the-year in a ditch near Horseshoe Lake and 
reported this as the first evidence of successful spawning of silver 
carp in Illinois waters and the United States. They felt that the 
species would be `established' in the state within the next ten years. 
Based on the occurrence of juvenile fish in Illinois waters, Pflieger 
(1997) felt that successful spawning of silver carp in Missouri seems 
inevitable. In the early 1980s commercial fishermen in Arkansas had 
caught 166 silver carp from seven different sites; however, during an 
intensive 1980-1981 survey to determine the distribution and status of 
bighead and silver carp in state open waters, Arkansas Game and Fish 
Commission personnel were unsuccessful in procuring any additional 
specimens (Freeze and Henderson 1982). Although Arkansas state personnel
 did not find young-of-the-year fish, several specimens taken by the 
commercial fishermen were sexually mature and exhibited secondary sexual
 characteristics (Freeze and Henderson 1982). Nevertheless, Robison and 
Buchanan (1988) reported that there was still no evidence of natural 
reproduction in Arkansas waters. Rinne (1995) listed silver carp as 
introduced to Arizona in 1972 and denoted it as established. Apparently 
in reference to the same record, William Silvey of the Arizona Game and 
Fish Department recently informed us that the only silver carp 
documented in Arizona open waters was a population inhabiting an urban 
lake in Chandler during the early 1970s. However, further investigation 
has shown that it was most likely a bighead x grass carp hybrid 
population (P. Marsh, pers.comm.). That population, along with a large 
population of diploid grass carp, was exterminated in 1975 or 1976 by 
personnel from the Arizona Game and Fish Department and Arizona State 
University (W. Silvey, personal communication). Pearson and Krumholz 
(1984) documented records from the Ohio River, but they did not include 
it as one of the species that exist in well-established, reproducing 
populations. Etnier and Starnes (1993) provided information on silver 
carp, but by publication they were unaware of any records of the species
 in the state of Tennessee.
Impact of Introduction: Pflieger
 (1997) considered the impact of this species difficult to predict 
because of its place in the food web. In numbers, the silver carp has 
the potential to cause enormous damage to native species because it 
feeds on plankton required by larval fish and native mussels (Laird and 
Page 1996). This species would also be a potential competitor with 
adults of some native fishes, for instance, gizzard shad, that also rely
 on plankton for food (Pflieger 1997).  A study by Sampson et al. (2009)
 found that Asian carp (silver and bighead carps) had dietary overlap 
with gizzard shad and bigmouth buffalo, but not much of one with 
paddlefish.