UPPER DELAWARE RIVER — With the ability to ‘walk’ on land, and breathe air, the northern snakehead (Channa argus), called by some “Frankenfish,” poses a real threat to river ecosystems. It has arrived in the Upper Delaware Scenic and Recreational River.

The first of its kind was caught locally by a 14-year-old client of licensed fishing guide Dustin Mason on July 31 between Damascus and Callicoon. The client was celebrating his birthday and Mason said that they were fishing for small mouth when the fish was hooked next to the boat. “As we reeled him in, I knew exactly what it was.”

The northern snakehead is a non-native invasive species that is a voracious predator, according to Don Hamilton, natural resources chief for the National Park Service (NPS). While primarily a fish eater, it also eats amphibians and invertebrates. It is of particular concern, he said, because it has the potential to outcompete and displace native species and alter aquatic food webs of the Delaware River. “If this was a pond system, you could eradicate them by using rotenone to kill off all the fish in the pond, a step which the New York State Department of Environmental Conservation has taken in the past in dealing with these fish,” emphasizing the seriousness of the concern about them. “You can’t do that in a river system like this,” he said.

NPS will be coordinating with the New York State Department of Environmental Conservation (DEC) and the PA Fish and Boat Commission to “come up with a game plan. There is no silver-bullet approach to dealing with this fish,” Hamilton said.

The fish can occupy a variety of aquatic habitats and can tolerate a wide range of water temperatures, from 32 to 90 degrees F. What this means is that “the winter may not kill or drive them downriver,” Hamilton said. Additionally, the fish can survive in very low dissolved oxygen water, and is an obligate air breather that can “come onto land, travel a short distance and enter a different water body.”

The fish can grow to 33 to 34 inches long. Three-year-old fish are 14 to 25 inches long; the fish become sexually mature at two to three years old and, during spawning, may lay 22,000 to 115,000 eggs, Hamilton said. The fish caught, according to Mason, was 20 inches.

The northern snakehead is native to Asia and is a prized eating fish that was at one time imported as part of the live-food fish market. People who want to eat them keep them alive until ready to cook and consume, not unlike a lobster. In 2002, the U.S. Fish and Wildlife Service prohibited the importation and interstate transport of all snakeheads under the Lacey Act, and it is also unlawful to possess, sell, or transport them live in both NY and PA. Northern snakeheads have been showing up with increasing frequency in parts of the world far outside their native range in recent years.

If you think you have caught a northern snakehead, it is important to kill it immediately, take a picture, record where you caught it and freeze it in case it is requested by fisheries agencies for identification.

“There are other non-native fish in the system,” Hamilton said. “But not anything as potentially disruptive or damaging as the northern snakehead. As reports come in and we get a better sense of their distribution, we’ll consult with other agencies to determine a viable course of action.”

Click here for an interview with Friends of the Upper Delaware Executive Director Jeff Skelding.