Poor water quality can drive snakehead fish to walk on land, research shows

If taking over a river ecosystem isn’t enough for the invasive northern snakehead fish known as “fishzilla,” walking on land is another feat of the fish, according to new details released by a Wake Forest University researcher.

The invasive fish has a snakelike appearance with its sleek shape and pattern of coloring. The northern snakehead is known as being somewhat unstoppable in parts of the United States. Native to China, Russia and South Korea, the snakehead is a predatory fish that competes with native fish for food, potentially impacting their populations.

The recent discovery of the snakehead by an angler in the Monongahela River in Pittsburgh’s Duck Hollow neighborhood, which was confirmed by the Pennsylvania Fish and Boat Commission, has created concern.

A Wake Forest news release on the most recent snakehead fish research noted the discovery of the invasive species in one of Pittsburgh’s three rivers as well as a pond in Gwinnett County, Ga.

Wake Forest researcher Noah Bressman reported polluted water conditions could cause snakeheads to take to land in search of another body of water. Water high in salinity and acidity and stagnant water with too much carbon dioxide could drive the fish to land, Bressman said.

Although it remains unclear how often snakeheads leave water voluntarily and cross over land to invade other waterways, Bressman said these findings can help natural resources agencies plans to contain the fish.

Bressman’s article was published Oct. 21 in Integrative Organismal Biology.

His article also explored how the fish manages to move on land.

Snakeheads can “walk” on land, surviving up to 20 hours if conditions are right, according to other researchers and Bressman.

For his research, Bressman observed the snakehead “moving in a way no other amphibious fish do: It makes near-simultaneous rowing movements with its pectoral fins while wriggling its axial fin back and forth.”

The movements allow the fish to travel across uneven surfaces.

Bressman told the Tribune-Review that although accounts of “walking” northern snakeheads are rare, “just one instance of this occurring can be enough for populations to establish elsewhere.”

“People are probably more likely to release them into other bodies of water, or may try to dispose of them by tossing them into the woods or leaving them on the ground to die (probably not knowing they can breathe air), which can help facilitate their spread,” he said.

Given the invasive fish’s presence in the eastern part of Pennsylvania, the Fish and Boat Commission has been asking anglers to keep an eye out for the snakehead fish. If they catch one, they are advised to kill it, freeze it for examination and alert the closest commission regional office. The southwest region office can be reached at 814-445-8974.

At this point, the commission believes the Monongahela River snakehead was an isolated finding.

Pennsylvania law prohibits the possession, sale, purchase and transport of live snakeheads. Unfortunately, the fish gives a good fight when it is caught and is tasty, making it attractive to some anglers.