Like Godzilla, “Fishzilla” hails from Asia
Its immense reproductive capacity, ability to skulk about on dry land, and avid appetite for all manner of aquatic life (as well as a few terrestrial species) has earned this invasive fish some apt labels, chief among them Fishzilla and Frankenfish. The northern snakehead (Channa argus) is a fierce apex predator which hails from southeast Asia, and breeding populations are known to be established in Delaware, Georgia, Mississippi, Missouri, Virginia, Maryland, Pennsylvania, and downstate New York. Individual specimens have also been found in eight other states.
It was hit hard with the ugly stick
If and when you encounter this water-monster, you’ll know right away that it’s something unusual. The large reptilian scales on its head and cylindrical body profile account for the snakehead’s common name. Brown-and-olive blotches on its sides are reminiscent of yellow perch body markings, and it has a single dorsal fin running the length of its body, with a very long anal fin. Northern snakeheads may reach lengths of over three feet and weigh more than fifteen pounds. Although they bear some similarities to native burbots (Lota lota) and bowfins (Amia calva), the single most important distinguishing feature is that our native fish species lack prominent head scales.
A fierce, hardy, prolific, apex predator
As with many invasive species, snakeheads have no natural enemies in North America. They’re also tolerant to a fault. Snakeheads eat native zooplankton, fish, amphibians, reptiles, invertebrates, and reportedly, small birds and mammals, using their prodigious teeth to sever prey fish one-third their size.
Not only can they thrive in water from 32 to 80 degrees, they will endure highly turbid, anoxic conditions by gulping air into a chamber in their heads.
Plus, their talent for surviving for up to four days on land and wriggling as far as a quarter-mile gives them an edge in seeking better habitats.
Their appetite for reproduction seems to mirror their hunger for native fish. Snakehead females lay between 1,300 and 1,500 eggs during each spawn. And they spawn five times a year. Yeah. Obviously, this species has the potential to drastically alter aquatic ecosystems, possibly even extirpating some native fish species. It could lead to significant damage to the tourism industry – and thus the economy in general – in the eastern Lake Ontario-St. Lawrence Seaway region should it become established here.
The snakehead’s New York debut
No one knows how snakefish were introduced to New York State – there is some evidence that a few infestations were deliberate. Biologists from the U.S. Geological Service think the species first arrived in the U.S. destined for live-fish markets. Juvenile snakeheads can be unknowingly moved in recreational boat bilge water or transported as live bait minnows. Unfortunately, release from home aquariums into surface water is still a potential means of invasive species introduction.
The first reported northern snakehead in the state was in 2006. According to the New York State Department of Environmental Conservation (NYSDEC), snakeheads are now present in a number of ponds and slow-moving waterbodies within NY City, but that the Walkill River infestation was eradicated by 2009. The NYSDEC prohibits possession, sale or transport of any snakehead species, and federal law forbids interstate movement of same. To the north, Ontario likewise has outlawed possession of the species.
Given that northern snakeheads would flourish in any NY State waters, please keep an eye out for this invasive fish. If you catch a suspected snakehead, notify the NYSDEC at firstname.lastname@example.org or (518) 402-9425, or report it to the online platform iMapsInvasives at https://www.nyimapinvasives.org/. If indeed it is “Fishzilla,” remember that authorities only need the head to confirm its identity. I’m told snakeheads are delectable.
Paul Hetzler is a naturalist, Certified Arborist, and a former Cornell Cooperative Extension educator.