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| NAS - Nonindigenous Aquatic Species |
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Common Name: northern snakehead
Synonyms and Other Names: Ophiocephalus pekinensis; O. argus warpachowskii; O.a. kimurai
Taxonomy: available through 
Identification: A long, thin fish with a single dorsal fin running the length of the fish. Also has a single long anal fin similar to our native species, the bowfin (Amia calva). Overall color is brown with dark blotches. It has a somewhat flattened head with eyes located in a dorsolateral position on the anterior part of the head; anterior nostrils are present and tubular; dorsal and anal fins are elongated, and all fins are supported only by rays (Courtenay and Williams 2004).
Size: Maximum size exceeds 85 cm (33 inches).
Native Range:
China, Russia and Korea (Courtenay and Williams 2004).
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Hawaii |
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Interactive maps: Continental US, Alaska, Hawaii, Caribbean
The first report of this species in the United States came from Silverwood Lake, California in 1977 (Courtenay and Williams 2004). Two fish were captured from the St. Johns River below Lake Harney in Florida early in 2000. There were uncomfirmed reports of another 3 fish nearby. A specimen was collected in Lake Michigan, Burnham Harbor in downtown Chicago, Illinois in 2004 (D. Chapman, pers. comm.). In June 2002, an established population of this species was discovered in a pond in Crofton, Maryland. This population was eradicted by state biologists using rotenone. Fish have been reported from two locations in Massachusetts; once in 2001 and again in 2004. In July 2005, they were reported in Meadow Lake in Queens, New York and persisted in 2006 (J. Pane, pers. comm.). In late May and early June 2008, three snakeheads were collected from stream in Wawayanda, New York (M. Flaherty, pers.comm.). An attempt was made to eradicate this population in 2008. Two fish were reportedly caught by anglers in August 2002 from Lake Wylie, North Carolina. Five years later in 2007, a large adult was caught by a fisherman in South Fork Catawba River in North Carolina (J. Rash, pers. comm.). In July 2004, several individuals were captured from a pond in FDR Park in Philadelphia, Pennsylvania. The following year young snakeheads were captured in the park pond (R. Worthington-Kirsch, pers. comm.). In June 2008, a specimen was collected by the city water department from the Schuylkill River in Philadephia (J. Perillo, pers. comm.).
Beginning in April 2004, several fish were captured from the Potomac River in Maryland and Virginia. As yet, it is not known if these fish came from the established population in the Crofton pond. Another specimen was collected in Dogue River in Fairfax County, Virginia. A fish was collected from Massey Creek and in 2005 a breeding female was found in Little Hunting Creek, a tributary of the Potomac, Virginia. Many others have been collected in 2006 and 2007 in the Potomac basin centering around Dogue and Little Hunting creeks in Virginia and from the Anacostia River in Maryland (J. Odenkirk, pers. comm.). In April 2008, the discovery of a single specimen in a ditch near Monroe, Arkansas, led to the determination that a population appears to be established (L. Holt, pers. comm.).
Ecology: This species reaches sexual maturity in 2 to 3 years at approximately 30-35 cm (12-14 inches) in length. Females release 1,300 to 15,000 eggs per spawn, which can occur 1 to 5 times per year. The floating eggs take 28 hours to hatch at 31oC, 45 hours at 25oC and much longer at cooler temperatures. Larvae remain in a nest guarded by their parents until yolk absorption is complete at approximately 8 mm in length. At approximately 18 mm the young begin feeding on small crustaceans and fish larvae. The northern snakehead has been reported to be an obligate air breather, which means that it can live in oxygen-depleted waters by gulping air at the water's surface and survive several days out of water if kept moist.
Means of Introduction: This fish is popular in the Asian food market and most introductions were likely released for this purpose. This was the case in the founding individuals of the Crofton pond population in Maryland.
Status:
Channa argus is not established in California, Florida, Massachusetts, New York, and North Carolina where a few individual fish have been collected. However, the northern snakehead was eradicated from the Crofton pond in Maryland where it was established. The species is well established in the Potomac River and several of its tributaries in Virginia and Maryland. Although young fish were found, the status of the Philadelphia population is uncertain. Officials believe fish may have gotten into the lower Schuylkill River and Delaware River in Pennsylvania and see no practical means to eradicate them.
Impact of Introduction: Specific impacts are unknown surrounding the Potomac population. It is too soon to make that determination. These predatory fishes compete with native species for food and habitat. Juveniles eat zooplankton, insect larvae, small crustaceans, and the fry of other fish. As adults they feed mostly on other fishes, with the remainder of their diet comprised of crustaceans, frogs, small reptiles, and sometimes small birds and mammals.
Remarks: Channa argus prefers stagnant shallow ponds, swamps and slow streams with mud or vegetated substrate, with temperatures ranging from 0 to >30oC. There is no evidence that juveniles or adult snakeheads escaped from the Crofton ponds. The northern snakehead has a wider latitudinal range and temperature tolerance than other snakehead species. It also seems to be adaptable to a wide range of aquatic environments, as evidenced by the spread of reproducing, introduced populations in Asia and
Courtenay, W. R., Jr., and J. D. Williams. 2004. Snakeheads (Pisces: Channidae) -- A biological synopsis and risk assessment. U.S. Department of the Interior, U.S. Geological Survey Circular 1251, 143 p.
Other Resources:
USGS Snakehead photo gallery
USFWS Final Rule
Do you know the difference (ID guide)
Snakeheads (Pisces, Channidae) - A Biological Synopsis and Risk Assessment by Courtenay and Williams (March 2004) or download a 53.8 MB PDF version.
Channa argus (Global Invasive Species Database)
Author: Fuller, P. F. and A. J. Benson
Revision Date: 1/7/2009 Citation for this information:
Fuller, P. F. and A. J. Benson. 2009. Channa argus. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.
<http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=2265> Revision Date: 1/7/2009
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