Subspecies Channa argus kimurai (Shih 1936): Described from two specimens of length 185 mm and 250 mm; it can be distinguished by its variation in body proportions. In particular, the lower dorsal profile and differences in the arrangement of teeth. The body colour is all white, a complete contrast to C. argus. Above the lateral line, some of the scales have a grey centre. Vertical fins are tipped grey (Galveston Bay Invasive Species Risk Assessment Invasive Species Summary).\n
Subspecies Channa argus warpachowskii (Berg 1949): A larger variant which can attain a size of 800 mm and a weight of 7 kg. Characteristics of C. argus warpachowskii include higher average ray counts than C. argus (50 to 53 in the dorsal fins and 33 to 38 in the anal fins) and smaller scales. The irregular blotches on the side of the body are dark brown, edged with black and the lower part of the head is covered with small, dark brown speckles (Galveston Bay Invasive Species Risk Assessment Invasive Species Summary).
Subspecies Channa argus argus is common in China and Korea whereas C. argus warpachowskii is found in the Amur River of Russia and China.
Principal source: Courtenay, W.R. Jr., & J.D. Williams. 2004. Snakeheads (Pisces, Channidae) - A Biological Synopsis and Risk Assessment. USGS.
Compiler: IUCN/SSC Invasive Species Specialist Group (ISSG)
Review: Expert review underway: Dr. Walter R. Courtenay, Research Fishery Biologist, Center for Aquatic Resources Studies, USGS Florida Integrated Science Center USA
Publication date: 2009-05-21
Recommended citation: Global Invasive Species Database (2024) Species profile: Channa argus. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=380 on 07-10-2024.
Ecosystem change: Left uncontrolled, this predatory invasive species is likely to expand its range and could permanently alter the balance of aquatic ecosystems throughout the Mississippi River basin (US Fish and Wildlife Service & Arkansas Game and Fish Commission. 2008).\n
Predation: Okado (1960, in Courtenay and Williams 2004), reported that this species is a voracious feeder of aquatic fauna. Northern snakeheads can eat prey up to 33% of their own body length with larger prey often consisting of loach, bream, carp and perch; other food items include crayfish, dragonfly larvae, beetles and frogs (Courtenay & Williams 2004). A total of 17 food items, including 15 fish species, were identified from stomach contents of (n= 219) northern snakehead from the Potomac River (Odenkirk & Owens 2007) between 2004 and 2006. Food items observed consisted mostly of banded killifish (Fundulus diaphanous) with white perch (Morone americana), bluegill (Lepomis macrochirus) and pumpkinseed sunfish (Lepomis gibbosus) also commonly consumed (Odenkirk & Owens 2007). Goldfish (Carassius auratus), gizzard shad (Dorosoma petenense), American eel (Anguilla rostrata), yellow perch (Perca flavescens), largemouth bass (Micropterus salmoides), spottail shiner (Notropis hudsonias), eastern silvery minnow (Hybognathus regius), mummichog (Fundulus heteroclitus), channel catfish (Ictalurus punctatus), green sunfish (Lepomis cyanellus), tessellated darter (Etheostoma olmstedi), frogs and crayfish were also consumed at low levels (Odenkirk 2006, in National Control and Management Plan for the Northern Snakehead Undated).\n
Competition: Northern snakeheads are capable of surviving in water with very low oxygen content, giving them a competitive advantage over species such as pike and bass that require more oxygen (Sea Grant Pennsylvania 2007).\n
Economic/Livelihoods: It could have significant negative economic impacts if it were to become established throughout the the Mississippi River basin (US Fish and Wildlife Service & Arkansas Game and Fish Commission. 2008).\n
Disease Transmission: The Northern snakehead is affected by the following parasites which are also known to affect native species in various parts of the world: Mysosoma acuta (also affects crucian carp), Henneguya zschokkei ? (also affects salmonids), Cysticercus gryporhynchus cheilancristrotus (also affects cyprinids, perches), Clinostomum complanatum (also affects perches) and Paracanthocephalus cutus (also affects cyprinids, escocids, sleepers and bagrid catfish) (for more information on parasites carried by the northern snakehead please see Courtenay & Williams 2004).
All snakeheads were banned from importation and interstate transport in the USA in October 2002 by the US Fish and Wildlife Service under the Lacy Act (NSWG 2006). In the USA anglers and commercial fisherman have been asked to kill and freeze all snakeheads rather than re-release them and immediately report them to the local Fish and Game Department (Sea Grant 2007). \n
Chemical: In Crofton pond, Maryland (USA) herbicides (Diquat Dibromide and Glyphosate) were used to lower oxygen levels, then a piscicide (Rotenone) was used to poison the fish (Hilton 2002). The total cost of this eradication in a 1.8 ha pond was estimated at $110,000 (Courtenay & Williams 2004). Eradication would be much more complicated in rivers, streams, or larger lakes. \n
Physical: Electrofishing and netting may provide a low level of control to established populations but would not result in eradication due to selectivity of certain size classes (NatMangPln).\n
Decision support tools for identifying potentially invasive non-native marine and freshwater species (fish, invertebrates and amphibians) have been adapted from Pheloung Williams and Halloy (1999) Weed Risk Assessment. Please follow this link to access the decision support tool and kit.
A Risk-assessment for non-native freshwater species in the UK is available for determining the level of potential invasion The assessment can aid resource managers in decision making when it comes to management strategies.