Invasion Of The ‘Frankenfish’

by Michele S. Byers, Executive Director, New Jersey Conservation Foundation

Snakehead. The name sounds foreboding, especially for those with “ophidiophobia,” otherwise known as fear of snakes. But this freshwater fish isn’t frightening because of its name; it doesn’t have a long, slithering body, venom-filled fangs or a coil-and-strike pose.

Instead, the Northern Snakehead is scary because it’s an alien invasive fish with the potential to disrupt the ecology of New Jersey’s rivers, streams and lakes by decimating native species. And it may be headed for the Pine Barrens, home to some of the most pristine waters and robust native fish populations in this state we’re in.

The snakehead threat is being taken seriously by the nonprofit New Jersey Academy for Aquatic Sciences, which plans to launch a research project to scientifically assess the damage the Northern Snakehead could cause if it takes hold in the Pine Barrens.

In a recent presentation to fellow scientists, Dr. Alejandro Vagelli of the Camden-based Academy says the snakehead has been detected in at least five locations in southwestern New Jersey, and one breeding population has been established in Stewart Lake in Gloucester County. Dr. Vagelli believes the snakeheads came from localized populations in south Philadelphia and are likely to continue to spread upriver on the Delaware and its tributaries, eventually reaching the Pine Barrens.

“If snakeheads can tolerate highly acid streams (of the Pine Barrens), their predatory behavior could dramatically and permanently alter the structure of local aquatic systems,” says Dr. Vagelli. “Most freshwater aquatic systems have already been dramatically altered by introduction of game fish and other organisms, pollution and altered stream flows, but many of New Jersey’s Pine Barrens waters are still contain pristine, native fish communities, not significantly altered by human-induced changes.”

The snakehead, Channa argus, is a native of Asia and was first spotted in Maryland in 2002. It is believed to have been introduced to East Coast waterways through the release of fish from pet store aquariums or by food suppliers specializing in live fish for Chinese restaurants.

Ecologists quickly dubbed it “Frankenfish” for its uncanny ability to survive where other fish cannot. To call it resilient is an understatement. It tolerates a wide range of temperatures, including freezing, and can breathe air, allowing it to move short distances across land from one water body to another.

It can survive in waters with very low oxygen, known as hypoxia, giving it a competitive advantage over many local species. Snakeheads also have high reproduction rates. Parents aggressively protect their nests, which may contain broods of up to 15,000 larvae! And they’re voracious eaters, competing with local species for food during all life stages. Juveniles grow into fierce adult predators, eating other fish, crustaceans, frogs, small reptiles, and sometimes even birds and small mammals.

In the unlikely event you would like more information about the Northern Snakehead – including photos, videos and links to numerous articles – go to the U.S. Department of Agriculture’s National Invasive Species Information Center at

If you think you have caught or found a snakehead, don’t throw it back in the water. Instead, double-bag and freeze it and contact the New Jersey Academy for Aquatic Sciences at 856-365-0352 or the U.S. Fish and Wildlife Service at 800-344-WILD (800-344-9453). Be sure to take note of the exact location of capture; this will help scientists determine the spread of the population.

And for more information about protecting our precious land and natural resources, please visit New Jersey Conservation Foundation’s website at or contact me at

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