Snakehead Fish Information Packet



Frankenfish: The Snakehead Invasion-67310387985Northern Snakehead FishPhoto by AP Photo/Ed Wray00Northern Snakehead FishPhoto by AP Photo/Ed WrayRecently, an invasive air-breathing freshwater fish known as a snakehead has generated national media attention as the latest invasive species to threaten native fish and wildlife resources and the economic sectors that depend on them. The discovery of the spread of the northern snakehead into Maryland waters brought the issue close to home. There are currently 28 recognized species of snakehead fish in the world. The species are organized into two main groups: the Channa from Asia, Malaysia, and Indonesia, and the Parachanna from Africa. Four of the Channa species have invaded the United States: the northern snakehead (Channa argus), the bullseye snakehead (C. marulius), giant snakehead (C. micropeltes), and blotched snakehead (C. maculata). They have been introduced into many countries as a food source, or they were aquarium releases. Snakehead species are important to the fishing industry in Asia and have been shown to become commercially fishable. In China and neighboring Asian countries, there is a large yearly demand for northern snakehead as a major food ingredient and a folk remedy. Singapore alone imports more than 1,200 tons of northern snakehead each yearThe first known report of a snakehead in the United States came from Hawaii in the 1800’s. There continues to be an established population of blotched snakeheads on the island of Oahu. The blotched snakehead in Hawaii has limited impact on native species because it differs in characteristics from the other species of snakeheads found in the contiguous (connected) United States. In 1968, a giant snakehead was taken from a pond in Rhode Island. Since then, wild northern snakeheads have been collected in Florida, California, Massachusetts, and most recently, Maryland in the summer of 2002. 356616036195000-673101658620Watch out for Fishzilla!Check out the link on the right!00Watch out for Fishzilla!Check out the link on the right!An established population of northern snakehead (Channa argus) was found in July of 2002 in a Crofton, Maryland pond (see page 3 of this handout). The Maryland Department of Natural Resources eradicated the population with the use of a fish toxicant (poison). Despite the efforts, there have been other reports of snakehead fish in Maryland: one bullseye snakehead captured in the Baltimore Inner 4834255322580Fish market sign at an Asian food market in Honolulu, Hawaii, showing snakehead availability. Photo by Pam L. Fuller, USGS.00Fish market sign at an Asian food market in Honolulu, Hawaii, showing snakehead availability. Photo by Pam L. Fuller, USGS.Harbor, and three giant snakeheads taken from different locations in Maryland. The Maryland discovery was especially disturbing because juveniles were found, indicating successful natural reproduction in the wild. Snakeheads have been imported into the United States for two reasons: as aquarium fish, and for use as food. The fish found in the wild were either stocked in an effort to establish a local food source, or aquarium owners released them once they no longer wanted to care for them. Prior to being added to the list of injurious wildlife under the Lacey Act in October 2002 (which banned import and interstate transport without a permit from the U.S. Fish and Wildlife Service), snakeheads were sold in pet stores and in live food fish markets and some restaurants in several major U.S. cities, including Boston, New York, and St. Louis. Authorities have confiscated live specimens in Alabama, California, Florida, Texas, Virginia, and Washington, where possession of live snakeheads is illegal. Since many species of Channidae can tolerate a wide range of temperatures, they can expand their range by swimming to adjoining waterways or can move overland to nearby waters.Sources:Recognizing northern snakehead. (US Fish and Wildlife Service, September 2003). Online at and -149860220980Left photo: Locations of northern snakehead collections and observations in the Mid-Atlantic. Maryland was the first location in the mid-Atlantic region. Right photo: Locations of northern snakehead observations in the United States.00Left photo: Locations of northern snakehead collections and observations in the Mid-Atlantic. Maryland was the first location in the mid-Atlantic region. Right photo: Locations of northern snakehead observations in the United States.Can you tell the difference?Comparing the Snakehead Fish to Native Species49149004229100Photo of four snakehead fish swimming and crawling in very shallow water. Most of their bodies are out of the water.00Photo of four snakehead fish swimming and crawling in very shallow water. Most of their bodies are out of the water.10795163830Snakehead FishBowfin Fish00Snakehead FishBowfin FishThe northern snakehead, Channa argus, is no ordinary fish. It is a voracious (hungry) top-level predator, meaning that it has no natural enemies, and could decimate populations of native fish. About 90% of its diet consists of other fish, though it also eats crustaceans (for example, crayfish), insects (for example, dragonfly larvae, and beetles), frogs, and plants. Although little information exists in the scientific literature regarding predation on snakeheads, juveniles (young) could be vulnerable to other predatory fishes, such as gars, larger sunfishes, bass, perch, and pike, and some wading birds once they leave the nest and their guarding parents. As adults though, the snakeheads can become the top predators within the freshwater fish community. Humans would be their sole predator - some species are considered a delicacy within their native ranges. 222251164590Watch how Snakehead Fish move on land!Check out the link below!00Watch how Snakehead Fish move on land!Check out the link below!The northern snakehead is highly adaptable to variable environmental conditions with latitudinal and climatic ranges greater than that of other snakehead species. In its native range (the Amur River basin and Songhua River of Manchuria; rivers of China and upper tributaries of Yangtze River basin in north-eastern Yunnan Province; and Korea), the northern snakehead can live in water with temperatures ranging from 0 to 30C (32 to 86F), with some species able to live in ice-covered waters. -1608455-3175The majority of snakehead species live in freshwater streams and rivers. Others can occur in freshwater swamps, ditches, ponds, and rice paddies. Snakeheads have little sacs above their gills that allow them to breathe air and survive for up to four days out of water, and survive for longer periods of time when burrowed in the mud. They are capable of traveling over land to new bodies of water by wriggling their bodies over the ground. These features are adaptations to the season-al drying of shallow bodies of water in the snakeheads native habitat in China that allow it to disperse (spread) widely should local conditions become unfavorable. 4305300-8255000The species has the potential to wipe out a small pond and stream ecosystem, moving from failed ecosystem to failed ecosystem as the available prey becomes exhausted in the area. It is capable of surviving in much of North America should it become established. An established population of snakeheads in Maryland could have long-term disastrous consequences for the ecology of the region.36055302035810004196080155575Juvenile snakeheads (fry) cluster at the surface of their “nest”. Their parents will aggressively guard their nest for 3-4 weeks while the fry develop their fins, learn to school, and are ready to fend for themselves. Picture from USGS00Juvenile snakeheads (fry) cluster at the surface of their “nest”. Their parents will aggressively guard their nest for 3-4 weeks while the fry develop their fins, learn to school, and are ready to fend for themselves. Picture from USGSThe reproductive behavior of snakeheads is quite interesting. For most species, breeding occurs between June and August. Snakeheads form monogamous pairs that remain throughout the spawning season. Some species can breed up to five times a year, and females can lay as many as 100,000 eggs a year. Most (perhaps all) are nest builders. The northern snakehead, for example, builds elaborate nests by clearing an area of vegetation and weaving some vegetation into a column. The water-filled nests are about 2-3 feet deep and about 3 feet in diameter. During spawning the pair move up the column they built, and the male wraps his body around the female. The eggs are then released and fertilized, and they rise to the surface of the nest column. One or both parents fiercely guard the eggs. There have been reports of attacks against humans who approach a snakehead egg mass. Two species of snakeheads are mouth-brooders: one of the parents will carry fertilized eggs in its mouth cavity. When the fry hatch, they are retained in the mouth until their fins develop to the point the young can swim.Sources:Do you know the difference? (Virginia Department of Game and Inland Fisheries, May 2004). Online at Hilton, R. 2002. The northern snakehead: an invasive fish species. CSA. Online at Introduced Species Summary Project: Northern Snakehead (Channa argus). (Columbia University, Center for Environmental Research and Conservation, October 2004). Online at [Type a quote from the document or the summary of an interesting point. You can position the text box anywhere in the document. Use the Drawing Tools tab to change the formatting of the pull quote text box.]4000020000[Type a quote from the document or the summary of an interesting point. You can position the text box anywhere in the document. Use the Drawing Tools tab to change the formatting of the pull quote text box.]-60445655105400Source:Infographic from Cnews at from Cnews at World-Record Snakehead Fish Caught In U.S.Bill Chappell, National Public Radio405574527940Caleb Newton holds his record-setting Snakehead Fish.Photo by Griffin Moores/ The Free Lance-Star00Caleb Newton holds his record-setting Snakehead Fish.Photo by Griffin Moores/ The Free Lance-StarAugust 08, 201311:07 AM ET A Virginia man has caught the largest northern snakehead on record with a rod and reel, landing a 17-pound, 6-ounce specimen of the fish often called "Frankenfish" for their monster-like appearance and tenacious survival skills.Caleb Newton, a plumber who lives in Spotsylvania County, Va., caught the fish in June during a tournament on Aquia Creek, a tributary of the Potomac River that's near the Quantico Marine Corps Base.Newton tells the newspaper that it took about a minute to get the fish in his boat. And measuring three feet, it was a tight fit to get the record catch into his cooler, he says. But, he adds, it didn't give him a whale of a fight. "I caught one 13 pounds on Saturday, and that one fought harder," he tells the Free Lance-Star.Newton's fish bests the previous record catch of a 17-pound, 4-ounce northern snakehead in 2004 in Japan, according to the International Game Fish Association. The IGFA awards world records for seven varieties of the snakehead. The record-setter for the giant snakehead fish (Channa micropeltes) was hauled in earlier this year in Thailand — and weighed in at 26 pounds.Other than Newton's catch, one other IGFA record was set in America — a great snakehead that weighed 14 pounds was caught in Florida earlier this year. All the other snakehead records were set in Asia, where the fish is native. Northern snakeheads are known for having sharp teeth, slimy skin, a voracious appetite and the ability to survive on land for days at a time. A spawning population as found in a pond in Maryland near the Potomac River in 2002.The predator's move into U.S. ecosystems has spurred efforts to control its growth, including holding tournaments — and spreading the word that it's a tasty fish worth the trouble of catching. "It tastes very good. I like them deep fried or grilled with onions and butter," fisherman Brett Miron told Agence France-Presse last month at a tournament in Maryland.Source:Chappell, B. 2013. World-Record Snakehead Fish Caught in US. National Public Radio. Online at for Trouble in WheatonSnakehead Stalkers Hope to Come Up Empty as They Drain LakeBy David A. Fahrenthold, Washington Post Staff WriterFriday, April 30, 2004 -61595407670Maryland officials yesterday began the slow and messy process of draining a lake in Wheaton Regional Park, looking for northern snakehead fish where an angler hooked one Monday. Pine Lake, a five-acre body that is home to thousands of fish, turtles and other wildlife, will be emptied to its muddy bottom over the next couple of days, officials said. After the lake is emptied and the fish are removed, workers will look for any adult or baby snakeheads, as well as for the fish's eggs and floating underwater nests. If there is no sign of the fish, then the lake will be refilled and restocked. But if any more snakeheads are found, officials said, they would probably use a chemical poison on the lake -- the same treatment that the Crofton pond in Maryland received.In 2002, a fisherman visited a government office in Annapolis, Maryland, with a photograph of an unfamiliar fish he had caught and then re-released in Crofton pond. Biologists soon identified the fish as a Northern Snakehead. Authorities would find out that two years earlier, a Crofton resident wanted to make a soup for his sister who was ill. He called an Asian fish market in New York and ordered a couple of live northern snakeheads, prized in his native Hong Kong for their flavor and curative properties. But by the time the fish arrived, the man's sister had recovered.440563062865Department of Natural Resources fisheries biologists spray a poison into a Crofton, Md., pond.Photo by Steve Ruark, AP00Department of Natural Resources fisheries biologists spray a poison into a Crofton, Md., pond.Photo by Steve Ruark, APWith no need to make soup, the man placed the fish into an aquarium. The snakeheads began to grow, so he fed them more and more goldfish- up to 12 per day. It didn't take long for the creatures to wear out their welcome. The tree-bordered pond behind a Crofton shopping center seemed like an ideal new home, the man told investigators. And it was, from the snakeheads' point of view. They mated and had babies- lots of them. On August 18, Fisheries Service personnel first used herbicides (poisons for plants) to cause oxygen levels in the pond to drop, then used piscicide two weeks later to kill the remaining fish. The threat from Crofton had been eliminated. Now, authorities face a similar problem in Wheaton. The fish caught Monday was a female that was developing eggs but was not ready for them to be expelled and fertilized, state officials said. "It gives me some confidence that, yes, we've beaten the spawn," which for snakeheads comes in early summer, said Steve Early of the Department of Natural Resources. Draining the lake will cost the Maryland-National Capital Park and Planning Commission about $10,000, about half of which would go for labor costs, Berlage said. The other $5,000 will pay for the rental of six mechanical pumps, the largest of which are capable of moving 600 gallons of water a minute. Water will be sucked in by the pumps through a hose that is designed to keep large fish out. Smaller fish and fish eggs could be sucked in, but then filtered out and kept in large bags. Turtles, snakes and other wildlife are expected to leave on their own. As the water in the lake recedes, officials said, they will use electric shocks to stun the remaining fish. They will be removed and stored in holding tanks temporarily, officials said. The "electro-fishing" in Pine Lake began yesterday, and officials said it gave them cause for optimism. The fishing turned up eight species of fish, they said, but no more snakeheads like the 19-inch specimen that was hooked by a would-be bass fisherman on Monday. "To the best of our knowledge, this incident is restricted to a single fish," Early said. Even after the lake is drained, he said, an air-breathing snakehead could theoretically still hide in the mud. But he said workers would keep an eye out for one flopping in the mud, and rake over the bottom to make certain none was hiding. * Although snakehead fish were cleared from the Crofton and Wheaton ponds, unfortunately since this story was written, northern snakehead fish have now invaded through the Chesapeake Bay to Maryland. Virginia fisheries biologists believe that snakeheads originated from Dogue Creek and traveled along the Virginia shoreline to colonize creeks including Little Hunting to the north and Pohick and Occoquan to the south. The snakehead has since been found along 60 miles of the Potomac River and has made its way into the Chesapeake Bay and now a few have been found in the Patuxent River in Maryland.Sources:Fahrenthold, D.A. 2004. Fishing for Trouble in Wheaton, Snakehead Stalkers Hope to Come Up Empty as They Drain Lake: The Washington Post, April 30, 2004. Online at Hilton, R. 2002. The northern snakehead: an invasive fish species. CSA. Online at 1402080134620Hooking a Huge Fish!Check out the link on the right!00Hooking a Huge Fish!Check out the link on the right!491744074930The snakehead fish is prized for its healing properties in China, but has been illegal to import to the United States since 2002.Photo by New York State Department of Environmental Conservation00The snakehead fish is prized for its healing properties in China, but has been illegal to import to the United States since 2002.Photo by New York State Department of Environmental ConservationA Delicacy on Chinatown Plates, but a Killer in WaterBy LIZ ROBBINS and JEFFREY E. SINGERPublished: April 29, 2011 The walls in the basement of a building in Brooklyn’s Chinatown were whitewashed, and boxes of cleaning supplies were stacked on the red tile floor. But beneath the disinfectant smell, the unmistakable odor of fish lingered. That tenant, Yong Hao Wu, sold fish until October for his Howei Trading Company out of this shop on Eighth Avenue in Sunset Park. Mr. Wu is now out of business and under arrest because the authorities have accused him of illegally importing thousands of live snakehead fish. That the snakehead has been illegal to import into the United States since 2002 when it was found in a pond in Maryland has not diminished its demand — and perhaps has only fueled it. The fish, which has also been illegal to possess in New York State, has been sold in other markets like Boston and is also available through the Internet, officials with the United States Fish and Wildlife Service said. On Thursday, the authorities caught one of the fishmongers. Officials arrested Mr. Wu, 43, after an investigation that followed the seizure of 353 live snakeheads on the eve of the 2010 Chinese New Year, at Kennedy International Airport. Surveillance cameras led them to Howei Trading Company in Sunset Park, where officials found a tank filled with 82 more snakeheads. Mr. Wu was arraigned on Thursday night, charged on felony commercialization of wildlife and importing fish dangerous to indigenous fish populations. If convicted, he faces up to four years in prison. The authorities said Mr. Wu had declared 3,889 imports as “Chinese black sleeper fish,” but he later admitted that they were, in fact, snakeheads. If the freshwater fish escapes its tanks, or is intentionally released, it can slither to water on land for three days. It has been found in rivers and lakes across the country. In China, the snakehead is a sweet, meaty staple harvested in farms, and when boiled into soup, it is reputed to possess remarkable healing properties. But once outside of its natural river habitats in China, Korea and Russia, it is a rapidly reproducing predator with such a voracious appetite it can wipe out entire schools of fish and destroy an ecosystem. “The flavor is absolutely the best,” insisted a 60-year-old man who gave his name as Zhu. He was traveling on a private bus from the Chinatown in Flushing, Queens, to Sunset Park. “I’ve never tried it in the U.S., but it’s common and abundant in China. I’ve made it.” It is traditionally prepared as “one fish, two ways”: stir-fry the body and cook the head, tail and bone for soup. One fish, two ways. A delicacy in China, a killer in the United States.Source:Robbins, L. and Singer, J.E. 2011. A delicacy on Chinatown plates, but a killer in water. New York Times, April 29, 2011. Online at ................
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