Smithsonian team finds northern snakehead fish in Maryland’s Rhode River

A team of researchers and student summer interns from the Smithsonian Environmental Research Center in Edgewater, Md., discovered a northern snakehead (Channa argus) fish in the Rhode River in mid-July. This is the first report of this invasive species in this area, and may indicate a recent range expansion of the snakehead population.

Image left: The team of researchers and interns from the Smithsonian Enviornmental Research Center display the northern snakehead fish they recently found in the Rhode River.

Native to China, the first northern snakehead in Maryland was reported in 2002 in a Crofton pond, approximately 20 miles east of Washington, D.C. That population was eradicated, but a separate introduction occurred in the Potomac River in 2004, which led to the establishment of the northern snakehead in creeks and upper waterways of the Potomac in Maryland and Virginia.

The snakehead was caught during routine sampling at a long-term study site using a seine net. It represents the only specimen recorded for the Rhode River site in decades of such surveys. The fish was a mature female, 58 cm (23 inches) in length, caught near the headwaters of the Rhode River.

The northern snakehead is typically found in freshwater, although it can tolerate low salinity waters.  It was thought that higher salinity at the mouth of the Potomac may act as a natural barrier, serving to limit or reduce the fish’s spread to other tributaries. Due to extremely high levels of spring runoff in Upper Chesapeake Bay this year, salinities in Chesapeake tributaries are at some of their lowest levels in the last 30 years. This has potentially allowed the fish to move out of the Potomac and travel to other rivers via Chesapeake Bay.

Image right: The northern snakehead fish specimen recently found in the Rhode River.

Unlike most fish, the northern snakehead can survive up to four days out of water if kept moist. This ability comes from air chambers above their gills that act as a primitive lung. They are top-level predators with the ability to consume other fish and animals up to one-third of their own body size.  Northern snakeheads may cause declines in local fish and other organisms, causing potential changes to the food web.

The fish was caught by a research team of scientists and interns from SERC’s Marine Invasions Research Lab, which studies patterns and effects of biological invasions in coastal marine ecosystems throughout North America.  Information on this and other non-native species in Chesapeake Bay can be found at SERC’s website (

Any movement or possession of a live northern snakehead fish is a violation of state law. If you catch a Northern Snakehead, please do not release it. Anglers are asked to kill the fish and contact Maryland or Virginia Departments of Natural Resources.



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  • Matt Chew

    I’m disappointed to see the Smithsonian jumping on this bandwagon with all three feet. It is silly to suggest that snakeheads (or any other species) are “invasive” as if invasion is their objective. It is just as silly to suggest that low salinity “allowed” snakeheads to expand their Mid-Atlantic range, as if that’s what they had been hoping to accomplish. Snakeheads have no idea whether they’re in North America or Asia. They make no plans. All they can do is “follow their noses” to suitable habitat and attempt to eat whatever triggers that reflex. If you don’t want snakeheads in Maryland, fine. Good luck with that at this point. But don’t contribute to science illiteracy by making up scary stories about them.

  • huffy

    at malaysia we call it ikan haruan(snakehead)

  • Phil Caterino

    Sorry but they are invasive, maybe you can use “non-native” if you want but the sum total is that they are disaster to the natural ecosystem. One only has to have their nose broken in their boat by an “Asian Carp” or a kid drown in “Eurasian milfoil” to come to that realization.

  • Sandra | zapatillas de futbol sala

    I do not think an invasion of such species. I think this kind of animals are often sweet-water sea water not because they have sales. True, it may be living in the waters of estuaries between seawater and fresh water but I do so with an invasion of salt water. Which leaves me a little surprised is that this type of fish can live 4 days out of water just keeping it moist.

    I think if a fish that can harm people if I agree that all people can find you not to return to the water and finish with them.