Invasive snakehead fish found in the Schuylkill River: 'They're not supposed to be here'

PHOENIXVILLE, Pa. (WPVI) -- An invasive species of fish has once again reared its head in the Delaware River Watershed, leading to a warning from park rangers.

Park rangers at the Black Rock Sanctuary in Phoenixville, Chester County, say they found a northern snakehead last week and are asking anyone else who finds one to kill it on site.

"We catch and release," said AJ Porrino while fishing with his 6-year-old son at the sanctuary. "We don't really keep a lot of stuff."

He says he's come across the snakehead before and knows the risk.

"It has to get taken care of because it's an invasive fish," he said. "It could really offset the ecosystem, especially here where it's a small part of the river."

The northern snakehead is native to Asia, not Chester County.

Rangers Lauren Howard and Dustin Wolf, with Chester County Parks, found a snakehead in the Schuylkill River last week.

"They're not supposed to be here, and we really don't know long-term what that impact is going to have on our native species," said Mike Parker, spokesperson for the Pennsylvania Fish and Boat Commission.

Experts say the fish compete with native species for food, and they're unlike anything else found in the Delaware Valley Watershed.

"They can kind of move and slide along that grass or mud puddle to puddle pretty well, whereas other fish don't have that ability," he explained.

With that risk, rangers say it's illegal to keep a snakehead alive in Pennsylvania. Porrino says he and his son will oblige.

"We care about the Earth," he said. "We just try to do the right thing for Mother Nature.