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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Blotched Snakehead

Synonyms and Other Names: Ophiocephalus guntheri Sauvage and Dabry de Thiersant, 1874; O. marmoratus Brind, 1914; O. tadianus Jordan and Evermann 1902

Taxonomy: available through www.itis.gov

Identification: Snakeheads (family Channidae) are morphologically similar to the North American native Bowfin (Amia calva), and the two are often misidentified. Morphological differences used for identification between the two are depicted here. Snakeheads can be distinguished from Bowfin by the position of pelvic fins (directly behind pectoral fins in snakeheads, farther back on body in Bowfin) and the size of the anal fin (elongate and similar in size to dorsal fin in snakeheads, short and much smaller than dorsal fin in Bowfin). Additionally, Bowfin can be identified by the presence of a bony plate between the lower jaws (gular plate) and a distinctive method of swimming through undulation of the dorsal fin.

Blotched Snakehead is very similar to Northern Snakehead Channa argus, with slight differences in coloration: C. argus has an irregular blotch-like dark marking on the caudal peduncle, whereas C. maculata generally has a complete bar-like dark mark preceded by pale bar-like areas. Additional morpholgical differences include:

	C. argus	C. maculata
Lateral line scales	60-67	41-60
Transverse scales below lateral line	12-13	11
Dorsal fin rays	49-50	40-46
Anal fin rays	31-32	26-30

Morphological data summarized from Courtenay and Williams (2004).

Size: 33 cm TL (Okada, 1960)

Native Range: Asia: southern China, Hainan, and northern Vietnam (See Courtenay and Williams 2004).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Blotched Snakehead are generally found in shallow, vegetated areas of streams and ponds (Courtenay and Williams 2004). This species is a ambush predator, consuming fish, invertebrates, snakes, frogs, and small mammals (Axelrod et al. 1985; Courtenay and Williams 2004).

Means of Introduction: This species of snakehead was stocked as a food fish in Hawaii. Cobb (1902) stated that the China-fish or "Ophicephalus" was brought to Hawaii from China by the Chinese. However, Jordan and Evermann (1905) suggested that the species had been introduced into Hawaii from Borneo. Devick (1991b) indicated it was a deliberate introduction for use as a food fish (he listed the period of introduction as both 1800 and the 19th century). Jordan and Evermann (1902, 1905) reported that "China-fish" (along with goldfish) were generally sold alive to the Chinese [in Hawaii]. Borneo was mentioned as source by Jordan and Evermann (1902).

Unknown means in other areas.  The most likely mechanism is as a released food fish, as it is common in the food trade and rarely available in the aquarium trade (Courtenay and Williams 2004).

Status: Established in Hawaii. The species has been established on Oahu, Hawaii since before 1900 (Brock 1960; Maciolek 1984; Devick 1991a). Cobb (1902) and Jordan and Evermann (1902, 1905) reported that the species was fairly common in irrigation ditches and freshwater ponds in the Honolulu area. Maciolek (1984) noted that it was found in unspecified standing waters (e.g., reservoirs) on Oahu and reported it as actively spreading. Devick (1991a, b) listed the dominant habitat of this species in Oahu to be reservoirs or ponds. Failed in Massachusetts and North Carolina, as there are only single reports of one or few individuals from these states.

Impact of Introduction: Unknown. This predatory fish can impact native fauna; it feeds on crustaceans, large insects, frogs and fishes.

Remarks: This fish was originally identified as Channa striata in Hawaii for decades. Then in 2002, numerous old museum specimens collected in Hawaii were examined and identified all as C. maculata (R. Britz pers. comm. as cited in Courtenay and Williams 2004). Cobb (1902) and Jordan and Evermann (1902) used the name "Ophiocephalus" for the snakehead introduced to Hawaii. Jordan and Evermann (1905) recognized it as Ophicephalus striatus and reported taking ten specimens from a site in the Honolulu area in 1901. In his book entitled "A history of fishes," Norman (1958, and earlier editions) stated that snakeheads or "Ophiocephalus" "are carried alive by the Chinese to San Francisco and to Hawaii, where they are now naturalised and known as China-fishes." This led some to believe that snakeheads had been introduced to California. Dill and Cordone (1997) investigated the report with respect to San Francisco and concluded that, although snakeheads apparently appeared in Chinese markets in that city, it was not known from open waters.

Voucher specimens: Hawaii (USNM 126588, 380264); North Carolina (NCSM 53258). Jordan and Evermann (1905) referenced specimen(s) No. 03585 [probably U.S. Fish Commission or Bureau of Fisheries label].  There are two undated collections from Hawaii at the California Academy of Sciences CAS-SU 8133 and CAS-ICH 17710. Few details are given, both are likely from the early 1900s.  Courtenay and Williams (2004) mention collections at the Bishop Museum in Hawaii, BPBM 1759 and BPBM 3798.

A specimen collected from Lake Wylie, North Carolina, in 2009 was originally identified as Channa argus, but later genetic work combined with a closer morphological analysis determined the specimen to be Channa maculata (NCSM 53258; W. Starnes, personal communication).

 

References: (click for full references)

Axelrod, H. R., W. E. Burgess, N. Pronek, and J. G. Walls. 1985. Dr. Axelrod's atlas of freshwater aquarium fishes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Brock, V.E. 1960. The introduction of aquatic animals into Hawaiian waters. International Revue der Gesamten Hydrobiologie 45(4):463-480.

Cobb, J.N. 1902. Commercial fisheries of the Hawaiian Islands. Pages 381-499 in Report of the Commissioner for the year ending June 30, 1901. U.S. Commission of Fish and Fisheries, Government Printing Office, Washington, DC.

Courtenay, W.R., Jr., and J.D. Williams. 2004. Snakeheads (Pisces: Channidae): A biological synopsis and risk assessment. Circular 1251, US Geological Survey, Gainesville, FL. 143 pp.

Courtenay, W.R., Jr., J.D. Williams, R. Britz, M.N. Yamamoto, and P.V. Loiselle.  2004.  Identity of introduced snakeheads (Pisces, Channidae) in Hawai'i and Madagascar, with comments on ecological concerns.  Bishop Museum Occassional Papers 77:1-13.

Devick, W.S. 1991a. Disturbances and fluctuations in the Wahiawa Reservoir ecosystem. Project F-14-R-15, Job 4, Study I. Division of Aquatic Resources, Hawaii Department of Land and Natural Resources.

Devick, W.S. 1991b. Patterns of introductions of aquatic organisms to Hawaiian freshwater habitats. 189-213 in New directions in research, management and conservation of Hawaiian freshwater stream ecosystems. Proceedings of the 1990 symposium on freshwater stream biology and fisheries management, Division of Aquatic Resources, Hawaii Department of Land and Natural Resources.

Froese, R. and D. Pauly (eds). 2012. FishBase. World Wide Web electronic publication. Available from: http://www.fishbase.org.  Version (08/2012).

Jordan, D.S., and B.W. Evermann. 1902. Preliminary report on an investigation of the fishes and fisheries of the Hawaiian Islands. Pages 353-380 in Report of the United States Commissioner of Fish and Fisheries for the year ending June 30, 1901. U.S. Commission of Fish and Fisheries, Government Printing Office. Washington, DC.

Jordan, D.S., and B.W. Evermann. 1905. The aquatic resources of the Hawaiian Islands. Part I. The shore fishes. Bulletin of the U.S. Fish Commission 23:1-574.

Kottelat, M., A.J. Whitten, S.N. Kartikasari, and S. Wirjoatmodjo. 1993. Freshwater fishes of Western Indonesia and Sulawesi. Periplus Editions, Ltd., Republic of Indonesia.

Maciolek, J.A. 1984. Exotic fishes in Hawaii and other islands of Oceania. Pages 131-161 in W.R. Courtenay, Jr., and J.R. Stauffer, Jr., eds. Distribution, biology, and management of exotic fishes. The Johns Hopkins University Press, Baltimore, MD.

Okada, Y., 1960. Studies of the freshwater fishes of Japan, II, Special part: Prefectural University of Mie. Journal of the Faculty of Fisheries 4(3): 1-860.

Roberts, T.R. 1989. The freshwater fishes of Western Borneo (Kalimantan Barat, Indonesia). Memoirs of the California Academy of Science 14. California Academy of Sciences, San Francisco, CA. 210 pp.

Smith, H.M. 1945. The fresh-water fishes of Siam, or Thailand. Bulletin of the U.S. National Museum (Smithsonian Institution) 188:1-622.

Talwar, P.K., and A.G. Jhingran, editors. 1992. Inland fishes of India and adjacent countries. A.A. Balkema, Rotterdam, The Netherlands.

Other Resources:
Snakeheads (Pisces, Channidae) - A Biological Synopsis and Risk Assessment (March 2004) or download a 7.60 MB PDF version.

Author: Nico, L.G., P.L. Fuller, and M.E. Neilson

Peer Review Date: 3/24/2014

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.