“More likely, it would be reintroduction by someone who wanted to recreationally fish for them. Or someone who wanted them to establish a population in order to eat them,” he says.

Landsman adds that’s how snakeheads first got into the lower Potomac. He says they feast on the river’s native fish.

“The northern snakehead is actually from China. It’s not native to this area. It was found in the early 2000s in Maryland. It’s not known how they came here, but it’s assumed to be from fish markets,” he says.

Now that snakeheads are above Great Falls, they could invade the rest of the Potomac River and its watershed, according to Landsman.