Of the 28 species of snakehead, 25 are classified under the genus Channa and are native to southern and eastern Asia and 3 are classified under the genus Parachanna and are native to Africa. Snakehead have the ability to breathe air and live out of water for days and this makes them a popular fish for consumption in its native range. Live snakehead sold in North American fish markets and in the pet trade is the most likely explanation for its release. There are now bans on the live buying and selling of snakehead in Ontario and in parts of the U.S.A.

Characteristics

The body shape of most species of snakehead look very similar to our native bowfin. They are similar bowfin with their long, cylindrical shape, their long dorsal fin and their rounded tail fin. However, the snakehead has a very long anal fin that starts half way down the body, a pelvic fin that is located close to its head, and enlarged scales on the head much like a snake, hence its common name. They also have a large mouth with several sharp, canine-like teeth on the lower jaw. Northern snakehead can reach a maximum length over 80 cm (31.5 in.) and a weight of 7 kg (15.4 lbs). It reaches sexual maturity in 2 to 3 years where females release 1,300 to 15,000 eggs per spawn (in the summer), which can occur 1 to 5 times per year. The adults build a floating nest for the eggs and aggressively protect their nests from predators. They guard the hatched larvae until yolk absorption is complete, then the young begin feeding on zooplankton, small crustaceans and fish larvae. As adults snakehead mainly consume fish but will also eat amphibians, crustaceans, insects, small reptiles and even small birds and mammals.

Snakehead can breathe with both their gills and a lung-like organ that, in fact, requires them to breathe (or gulp) air at the water's surface otherwise they will drown. This allows them to survive in water that have very low levels of oxygen and even survive out of water for several days if they're kept moist. Some species of snakehead can live for long periods of time burrowed in mud and can travel over land to invade new bodies of water. Northern snakehead can survive in temperatures ranging from 0 to 30° C. This makes the northern snakehead of most concern because of its ability to survive in cold temperatures making it able to survive in much of North America if it becomes established.

Distribution

Currently four species of snakehead has been recorded in open waters in the states of California, Florida, Hawaii, Maine, Massachusetts, Rhode Island and Maryland. Reports of northern snakehead have been limited to California, Florida, and Maryland. The status of the populations of northern snakehead in Florida are uncertain and the population in Maryland was eradicated by biologists in 2002. These releases are a result of people buying them live for consumption or aquariums and later releasing them in natural waterways. The Ontario and certain U.S. governments have recently banned the buying and selling of live snakehead.

Impact

All species of snakehead are voracious predators and with no known natural enemies they could have major impacts on native populations of fish. They can compete with native species for food and habitat at all stages in their life-cycle. Snakehead also host a number of pathogens that may or may not be transferable to native species. Since some species of snakehead also have the ability to travel overland, their ability to spread may not be easily controlled. Although we can only speculate on the impacts, snakehead are recognized to have the potential to seriously threaten native fish populations.

Prevention

Although bans for the live buying and selling of snakehead are now in place in Ontario and parts of the U.S., the threat still exists from intentional release by aquarium owners who own snakehead before the ban. Preventing the release of snakehead into Ontario waterways is our best defense and you can help in the following ways:

Aquarium Owners

The release of aquarium pets into Ontario waters is illegal. You can help prevent the spread of non-native (exotic) aquatic species by doing the following:

• Never release or flush unwanted aquarium pets or aquarium water into natural waters, drainage ditches or sewers.
• Drain aquarium water on dry land.
• Return or donate unwanted aquarium fish, reptiles, snails and plants to a pet store or a school.

Contact a local aquarium club or the Canadian Association of Aquarium Clubs, at (905) 682-2991 or on the Internet at www.caoac.on.ca to ask about a fish rescue program for unwanted aquarium pets. Report sightings or obtain more information on exotic species by calling the Invading Species Hotline at 1-800-563-7711.