Practical information to identify and manage non-native, invasive plants and animalsThe Quiet Invasion:
A Guide to Invasive Species of the Galveston Bay Area
Snakehead, all species|
Human HealthThe snakehead is an aggressive predator and although, not known to attack humans, may bite humans who venture close to a nest.
Prohibited ListsThis species is legally classified in Texas as exotic, harmful, or potentially harmful. No person may import, possess, sell, or place this species into state waters except as authorized by a rule or permit issued by the TPWD. A person may possess exotic harmful or potentially harmful fish (exclusive of grass carp) without a permit only if the fish have been gutted.
Introduction PathwaysSnakeheads were first discovered in the U.S. in Maryland in 2002. They were imported live to the U.S. via the food trade and later released into freshwater lakes and rivers. Once released the snakehead can reproduce and move into adjacent waterways. Although not well adapted to land travel, the Northern snakehead can survive out of water up to four days breathing oxygen (ISSG 2005a).
Geographic DistributionAs of 2010, species of Channa are not reported in Texas. However, four species of snakeheads have been found in the U.S. in 15 states including, Arkansas, California, Florida, Illinois, Hawaii, Main, Maryland, Massachusetts, New York, North Carolina, Pennsylvania, Rhode Island, Tennessee, Virginia, and Wisconsin (USGS 2009d).
Specific Primary HabitatsSnakeheads are known to inhabit a variety freshwater lakes, rivers, and streams. C. argus (Northern snakehead) prefers stagnant shallow ponds, swamps and slow streams with mud or vegetation (ISSG 2005a). C. micropeltes (giant snakehead) favors deep, standing or slow flowing water. C. marilus (bullseye snakehead) prefers deep, clear lakes and rivers with rocky or sandy substrate. C. maculata (blotched snakehead) is found in irrigation ditches and reservoirs in Hawaii (USGS 2009d).
Ecological, Economic, or Social ImpactSpecies of snakehead negatively impact freshwater ecosystems of the U.S. through predation on and competition with native species. In the U.S. snakeheads are known to feed on a variety of organisms native to North American waterways (see Feeding below).
Physical DescriptionSnakeheads have sharp teeth, a small head, and a torpedo-shaped body that narrows towards the tail. The dorsal and anal fins are typically long, extending towards the tail. Pelvic fins are lacking or are located close to the head. Colors can vary among species. Young of the Northern snakehead (C. argus) are golden brown to pale gray in color, turning dark brown and developing black splotches as they age. Adults can grow to be very large (more than one meter in length). Snakeheads are sometimes confused with the native bowfin (Amia calva), but are unrelated (TPWD 2007).
Reproduction CharacteristicsSnakeheads can reach reproductive maturity in 2-3 years. The Northern snakehead can spawn multiple times a year. Female snakeheads studied in the Potomac River were found on average to carry more than 40,000 eggs (Odenkirk and Owens 2007). Many snakehead species clear vegetation to create a round nest into which fertilized eggs float. Eggs hatch in 24 to 28 hours and parents guard the young in the nest until they are approximately 18 millimeters in length (ISSG 2005a).
FeedingJuvenile snakeheads feed on zooplankton, fish, insect larvae and small crustaceans. Adults eat fish (e.g. killifish, sunfish, and perch) (Odenkirk and Owens 2007) and other vertebrates, including frogs, small reptiles, birds, and mammals (ISSG 2005a).Snakeheads are active at dusk and dawn, feeding near the shore.
ControlSince early detection is key to preventing the spread and establishment of this species, regional/local monitoring or surveillance is essential. Snakeheads should not be imported or released in local waterways. If found in local waters, note the capture location, kill and freeze the fish, and notify the TPWD.
This species belongs to the following lists:
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Page Updated/Reviewed: 07/14/2010 11:14 AM |