Northern snakeheads tend to disperse after they are old enough to endure deeper water and stronger currents. Adults are quite mobile, unless they are guarding their young. When guarding their young the home range averages 1. However, the distance of dispersal is largely dependent on the season. The highest average dispersal distance being directly after the spawning season, and the shortest dispersal was during the actual spawning season.
Northern snakeheads were tagged in the Potomac River system to determine the home ranges of 42 fish. On average the fish dispersed up to 18 km, and one fish was recaptured 21 km from where it was originally tagged. Northern snakeheads are capable of producing a small array of noises. Mature northern snakeheads have been observed making grunting noises as they feed, and clicking noises as they rise to the surface to breathe.
Northern snakeheads also have good eyesight. They prefer to hunt in low light situations, and have even been known to attack insects and other non-aqueous animals that they see outside of the water e. Northern snakehead are also capable of chemical perception. Snakeheads can perceive when there is a wounded animal in nearby waters, or if there is a current feed taking place by smelling chemical traces of blood in the water.
The northern snakehead is a predatory fish species that feed mostly on other fish, frogs, freshwater crustaceans, and some insects. As juvenile fish, the northern snakehead commonly feeds on small crustaceans and other fish larvae. The northern snakehead becomes predominately carnivorous when they reach 4cm in length. In their introduced range, specifically in the Potomac River system, northern snakeheads have been found to prey upon banded killifish Fundulus diaphanous , white perch Morone americana , pumpkinseed fish Lepomis gibbosus , bluegill Lepomis macrochirus and goldfish Carassius auratus.
In their native range, some of the fish that northern snakeheads prey include perch Perca fluviatilis , carp Cyprinus carpio , bream Abramis , and loach Cobitis. Once seasonal water temperatures reach 10 degrees the northern snakeheads become fully active in their feeding habits. Northern snakeheads feed in schools, as many other snakehead species do, and prefer to hunt in low light scenarios. Courtenay and Williams, ; Odenkirk, et al.
Outside of humans Homo sapiens , northern snakeheads are not prone to predation. It is likely that any large fish-eating predator in their habitats might prey on them, such as larger fish, birds, crocodilians, turtles, otters, etc.
Large adult northern snakeheads are large enough that they may be the top predators in some habitats. In one study eastern mosquitofish, Gambusia holbrooki , were observed eating newly fertilized eggs in a northern snakehead nest. Channa eggs and fry are small enough to be attacked by aquatic invertebrate predators too, such as dragonfly nymphs Odonata or predaceous diving bugs Belostomatidae , if not protected by their parent.
The coloration pattern of these fish is probably cryptic, but this has not been shown experimentally. Courtenay and Williams, ; Landis and Lapointe, Newly hatched snakeheads feed on insect species until they reach a length of around 2 cm. As a result of this, they likely help to keep the number of many pest related insects at bay.
Northern snakeheads are an invasive species that could cause ecosystem disruption to their non-native environment. They have the potential to disrupt native aquatic foodwebs, by competing with native fish for prey and feeding directly on native fish, including desirable game fish.
Like most fish, northern snakeheads are also affected by several parasites, including myxozoans , tapeworms including Cysticercus , Gryporhynchus cheilancristrotus , trematodes such as Clinostomum complanatum and Posthodiplostomum , and acanthocephalans including Paracanthocephalus cutus. Courtenay and Williams, ; Landis and Lapointe, ; Nguyen, et al. In their native range, northern snakeheads are raised in commercial aquaculture for food.
It is the most important snakehead species in China, and an estimated tons are produced yearly, for food, in Korea. It is also stocked in many of its native ranges in order to be cultured as a sport fish. Also, in Europe and Japan, northern snakeheads are valued as pets and aquarium owners purchase them for this reason. Courtenay and Williams, In the United States and other introduced ranges, northern snakeheads have a negative economic impact.
They are known to deplete many freshwater game fish species, such as the largemouth bass, Micropterus salmoides , in the Potomac River system. Government agencies in the U. Courtenay and Williams, ; Gul, et al. The IUCN has not yet evaluated the conservation status of northern snakeheads. Given their wide range, and popularity in aquaculture, they are not in immediate danger, but native wild populations might be vulnerable.
In the United States, Channa argus is considered an injurious species, and state and Federal agencies are working to eliminate small populations and prevent its spread. All species of snakeheads Channidae are listed by the U. The FWS and state agencies urge anyone that catches a snakehead in the U. After obtaining and analyzing the specimen, MassWildlife confirmed this fish was a snakehead, an invasive species in Massachusetts.
This fish was most likely released by a pet owner when it grew too large for its aquarium. Possession and liberation of snakeheads are both illegal in Massachusetts. Transferring exotic fish into local waterways can cause a host of problems, including competition with native species and spread of disease. This recent catch is the fifth confirmed snakehead documented in Massachusetts since All snakeheads found in Massachusetts were adults, and MassWildlife has found no evidence of reproduction at any of the locations where the snakeheads were caught.
Anglers may confuse snakeheads with other native species like bowfin. Anyone who captures a fish that can be confidently identified as a snakehead should keep the fish, kill it, and report it to MassWildlife by emailing mass. MassWildlife encourages anglers who are less certain about the species of fish they have caught to send photos showing various angles of the fish. Under no circumstance should a suspected snakehead be transported to another location until identification is confirmed.
A northern snakehead was recently caught in the Callicoon area of the Delaware River. Given the right environmental conditions, this invasive species can prey on and compete with other fish, upsetting the natural balance of local ecosystems. This advisory follows the documented movement of 21 Northern Snakeheads past the Conowingo Dam into the Conowingo Pool, a mile-long section of the Susquehanna River located between the Conowingo Dam in Maryland and the Holtwood Dam in Pennsylvania.
Anglers are reminded that possession, transport, and importation of a live snakehead is unlawful in both Pennsylvania and Maryland. Any of these invasive fish that are caught should be killed and disposed of properly or consumed. Anglers who suspect they have caught a snakehead are encouraged to NOT release it, and report it to the PFBC at or by sending an email to tgrabowski pa.
For more information on Northern Snakeheads in Pennsylvania, including an identification guide, visit the PFBC snakehead resource page. The Georgia Department of Natural Resources' Wildlife Resources Division confirmed someone found a northern snakehead in early October in a pond on private property in Gwinnett County, marking the first time the invasive fish has been found in the state.
Fishermen who find a northern snakehead should take pictures, note where it was caught and then report it. The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Northern Snakehead. Smithsonian Institution. Smithsonian Environmental Research Center. Marine Invasions Research Lab. Division of Fish and Wildlife. The Northern Snakehead Channa argus , a fish native to China and Russia, has become a problem invasive species in several states, including Delaware.
Snakeheads have the ability to breathe air by using an air bladder that works as a primitive lung, allowing them to survive for up to four days out of the water; they can survive for even longer periods of time burrowed in the sediment. This unique adaptation and their ability to travel over land to new bodies of water by wiggling their bodies over the ground, gives the snakehead a competitive edge over other fishes in securing habitat and expanding its range. Physical removal of the fish using nets, traps, angling, electrofishing or biological control by introduction of predators are not likely to be successful for large infestations.
If the infestation is believed to be limited to a few individuals the above techniques may be successful in removing the target organisms.
If the infestation is within an impoundment with water level control capability, removing all water may be a viable control technique. However, a water drawdown effort would result in damage to many desirable plant and fish species. An effort could be made to capture and relocate desirable species, but this would be an expensive and lengthy undertaking.
Impoundments that are spring fed may be difficult to keep dry and the snakeheads may survive in the moist bottom sediments if any water is allowed to remain. Rotenone can be used to eradicate northern snakeheads from lakes and ponds; however, this chemical is not a selective piscicide and is effective against nearly all species of fish, native and non-native. Northern snakehead has a mouthful of long, sharp teeth. Range Outside its native range, northern snakeheads have established breeding populations in the states of Virginia, Maryland, Pennsylvania and New York.
Possible impacts of Northern Snakehead in Ontario The northern snakehead could spread throughout the Great Lakes watershed and seriously threaten native fish and invertebrate populations in Ontario. The northern snakehead has no natural enemies in North America. It eats native zooplankton, fish and fish larvae, frogs and toads, invertebrates, insects, small reptiles and even small birds and mammals.
Because the northern snakehead is highly adaptable it is likely to thrive in Ontario waters. How to identify Northern Snakehead The northern snakehead can grow up to 85 centimetres long and weigh as much as seven kilograms. Check the chart below to know if you have a snakehead, a bowfin or another species.
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