NORTHERN SNAKEHEAD. Overview. Identification. Nonindigenous Occurences

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1 NORTHERN SNAKEHEAD Overview The northern snakehead is one of 29 species in the snakehead (Channidae) family, found in habitats where climatic conditions range from cold-temperate to tropical. Snakeheads are freshwater fish and nonnative to North America. Unique to the snakehead family is their ability to breathe air using specialized tissue located in a series of spaces toward the back of their head. The folded tissues in these spaces have a high surface area, allowing for the exchange of oxygen between the air and their blood. The northern snakehead (Channa argus), native to Russia, China, and Korea, populates areas where the prevailing climate is cold-temperate. Consumed as a food species in Asia, the snakehead was imported into the United States prior to 2002 by fish farm operations for the live food fish market. Other vectors of introduction and spread in North America include the aquarium trade, releases into natural waters associated with cultural and religious rituals, and unauthorized release during recreational fishing activities. While the northern snakehead is not a threat to human health or safety, it has voracious feeding habits, preying upon other fish, microscopic zooplankton juvenile and adult insects and crustaceans and, potentially, frogs, small reptiles, birds and small mammals. This behavior can impact native members of the ecosystem by severely altering their resource availability and feeding habits. Sport fishing (e.g., bass and crappie) may also be impacted by the northern snakehead through either direct predation on important native sport fish or by depleting the food supply of native sportfish. As the case with other invasive fish, there is concern over the snakehead s potential to transfer harmful pathogens to native fish populations. The northern snakehead has numerous characteristics that contribute to its invasiveness, including a high reproductive capacity. They reach sexual maturity at 2 to 3 years of age and females produce eggs several times per year, releasing tens of thousands of eggs per spawn. Unlike most native fish, northern snakehead exhibit strong parental care behavior, giving this species an advantage by increasing the survival rate of the young. They also have a physiological hardiness that allows for a tolerance to a wide range of environmental conditions. Although the northern snakehead inhabits many types of aquatic habitats, it prefers stagnant, shallow ponds, swamps and slow streams with mud or vegetated substrate, with temperatures ranging from 32 to > 86 o F. Snakeheads can survive in water with very low levels of oxygen, providing a competitive advantage over native species, such as trout, pike, and bass, which require more oxygen in the water. With their ability to breathe air, the snakehead can survive for up to four days out of water. Several species of snakeheads have the ability to wriggle a short distance overland, by flexing their body and pushing with their tail, while using their broad pectoral fins to stabilize their head. Photo: U.S. Geological Survey Identification The northern snakehead has a long narrow torpedo-shaped body which tapers toward the tail. Their dorsal and anal fins are elongated. Snakeheads have a small head with forward-facing eyes, a protruding lower jaw and large mouths with sharp, conspicuous teeth. The color of young northern snakehead is golden brown to pale grey, changing with age to a darker brown with dark brown or black blotches. They can easily be confused with our native bowfin and burbot. Size: Can reach up to 40 inches in length and 15 pounds in weight Native Range: China, Russia and Korea Photo: reuters/corbis Nonindigenous Occurences Northern snakehead occurrences have been reported in Arkansas, California, Florida, Illinois, Maryland, Massachusetts, New York, North Carolina, Pennsylvania, and Virginia. In 2002, eradication of an established population in Crofton, Maryland was successful, and eradication efforts also have been conducted on established populations in Arkansas (where a live individual was found in 2008 along a gravel road). While the snakehead has yet to establish a reproducing population in the Great Lakes basin, an individual was collected in downtown Chicago in Burnham Harbor, Lake Michigan in Although this species has never been reported in any natural waters in Canada, in March 2008, it was seen for sale and was purchased live at a fish market in Vancouver. The specimen was observed to survive in a container with no water, on ice for nearly 24 hours (B. Cudmore, personal communication).

2 Means of Introduction and Spread: During the process of importation, the potential for snakeheads to survive in transit while being shipped overseas from Asia to North America is high. As air breathers, the northern snakehead species is capable of surviving hypoxic conditions (reduced levels of dissolved oxygen in water) and can even survive out of water for considerable periods of time as long as they remain moist. Vectors of introduction and spread include accidental and intentional releases associated with the trade of live organisms. Examples of pathways include the sale of snakehead in live fish markets, release of individuals to establish a local food source, live bait operations, ceremonial release as a prayer species, and disposal as an unwanted aquarium fish. Snakeheads also are readily available for purchase over the internet. The spread of the northern snakehead has also resulted from colonization of established populations through natural and man-made connections. Status: The northern snakehead is established in the Potomac River and its tributaries in Virginia and Maryland, as well as in the Delaware River drainage of New Jersey and Pennsylvania and Hudson River drainage of New York. Available data indicate that the snakehead has yet to become established in California, Florida, Massachusetts, and North Carolina, where only a few individual fish have been collected. The northern snakehead is considered a high-risk potential invader to the Great Lakes region due to its ability to survive out of water for extended periods of time, high reproductive capacity, and broad and aggressive feeding habits. Distribution Maps: Geographic information on the location of aquatic invasive species sightings in the United States is made available through the U.S. Geological Survey, Nonindigenous Aquatic Species (NAS) program ( The NAS distribution maps for the northern snakehead can be found at: Management Control and Eradication: Potential methods for controlling invasive fish, such as the northern snakehead, are determined by the aquatic system where infestation occurs and the stage of invasion. For small infestations that are limited to a few individuals early in the process, physical removal of the fish using nets, traps, angling, electrofishing or biological control may be feasible. However, as the infestation grows in size, physical removal becomes a less viable option. If the infestation occurs in an impoundment with water level control capability, water removal is a potential control technique. The disadvantage to a water drawdown, however, is the potential negative impact to native populations of plants and animals. Chemical control with the piscicide, rotenone, has been used in attempts to eradicate infestations of northern snakeheads from creeks and ponds. Rotenone kills target fish by preventing them from removing oxygen from the water. Although use of rotenone and other similar toxins can be effective in eradicating invasive fish, these control substances can also result in killing non-target organisms. Large numbers of native fish species are generally sacrificed in the process of rotenone treatment. In many cases, however, rotenone is considered the only option to effectively eradicate infestations of northern snakehead and to ensure these fish do not spread to other waterbodies. In large lakes or riverine systems, such as the Potomac River where northern snakeheads populations (first detected in 2004) have become established on a wide-scale basis, eradication is considered nearly impossible and control efforts technically and financially challenging. As previously mentioned, eradication is considered more feasible when detection occurs early in the invasion process within aquatic systems that are relatively small and contained. This set of conditions existed for the infestation of juvenile snakeheads discovered in May of 2002 in the small storm water pond located in Crofton, Maryland. In treating this infestation, rotenone was applied to eradicate the snakehead in the pond and the two adjacent ponds with potential water connection. Fish kills included the northern snakehead along with other fish life in the pond. Although electrofishing and netting could have provided some level of control for the Crofton infestation, these methods would not have resulted in complete eradication due to their ineffectiveness in capturing all size and age classes of the fish. Other methods of control including explosives, draining of the aquatic system, and chlorine were not considered to be feasible options in eradicating the northern snakeheads in Crofton Pond. Another northern snakehead infestation of significance occurred in Piney Creek, part of the Mississippi River drainage of eastern Arkansas. A reproducing population was discovered in April of 2008 after a farmer observed an unusual fish moving on a gravel farm road near a ditch. In assessing the extent of the population distribution, Arkansas Game and Fish Commission (AGFC) discovered 90 northern snakeheads in an irrigation ditch on the farm where detection first occurred. More individuals were discovered in Piney Creek, located in close proximity to the farm. AGFC decided, if left untreated, this snakehead population could negatively impact the native fishery in the Piney Creek drainage with the potential to spread to the Mississippi River over time. Given the scope of the infestation, AGFC partnered with the U.S. Fish and Wildlife Service (USFWS) to plan and conduct rotenone treatment in the Piney Creek watershed. These efforts included an environmental assessment of the proposed treatment plan which was approved after a 30 day comment period. Eradication (initially scheduled for October, 2008), however, was delayed due to adverse weather conditions and abnormal rainfalls resulting from hurricanes in the fall. Although the delay provided some extra time to fine-tune the project design, treatment strategies and project mapping, there is concern that the prevailing conditions during this period facilitated further spread of the northern snakehead beyond its initial range. By the spring of 2009, eradication of northern snakehead in the Piney Creek watershed was implemented over the span of a week. The area of rotenone treatment included 4,000 acres of reservoirs, ponds, and backwaters and 400 miles of creeks and irrigation ditches. The complex habitat and terrain required application of rotenone by crews on foot and in boats and helicopters, by personnel riding allterrain vehicles, and by crews in special tracked aquatic vehicles called Marshmasters, supplied by the USFWS. The rotenone treatment operation was effective in killing thousands of snakeheads. To limit rotenone impacts to non-target fish downstream of the Piney Creek treatment area, a detoxification (potassium permanganate treatment) station was installed near the confluence of Piney and Big Creeks. Post treatment sampling continues in the area to monitor the situation. Unfortunately, living specimens have been found since the eradication effort, including some outside the treated watershed. Based on these findings, containment of the northern snakehead is no longer considered possible and it is expected that over time, this species will spread throughout Arkansas and beyond.

3 Current Regulations: In October 2002, the USFWS listed 28 species of snakeheads, including the northern snakehead, as injurious wildlife under the Lacey Act (18 U.S.C. 42). This injurious listing prohibits the importation and interstate transportation of the 28 snakehead species. On a state level, possession of live snakehead is illegal in Indiana, Illinois, Michigan, New York, Pennsylvania, and Wisconsin. In Canada, it is illegal to buy or sell live snakeheads in Ontario. Significant Contributions Provided by: U.S. Geological Survey, Nonindigenous Aquatic Species Program References: Cudmore, B. and N, Mandrak Risk Assessment for Northern Snakehead (Channa argus) in Canada. Fisheries and Oceans Canada. Massachusetts Department of Conservation and Recreation Rapid Response Plan for the Northern Snakehead (Channa argus) in Massachusetts. U.S. Fish and Wildlife Service. Recognizing Northern Snakehead (factsheet). U.S. Fish and Wildlife Service: Draft National Control and Management Plan for the Northern Snakehead (Channa argus). Studies, Assessments and Management Plans Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species (2009) Commission for Environmental Cooperation These guidelines lay out a standardized process for evaluating the risk to biodiversity of introducing aquatic nonindigenous organisms into a new environment. Chapter two of this report provides a case example of risk assessments of several species of snakeheads to three North American countries. Northern Snakehead Channa argus Eradication in Piney and Little Piney Creeks, Arkansas: Operation Mongoose (2009) Arkansas Game and Fish Commission This report provides an after-action assessment of an eradication operation targeting a northern snakehead infestation located in the Piney Creek watershed of eastern Arkansas. The report discusses the invasive characteristics of northern snakehead and the different stages of eradication efforts including: initial discovery, scope of infestation, project mapping, treatment methodology, and post treatment monitoring. Environmental Assessment for Northern Snakehead Eradication and Restoration of Native Fishery to the Piney Creek Drainage, Lee County and Monroe County, Arkansas (2008) U.S. Fish and Wildlife Service, Arkansas Game and Fish Commission This environmental assessment was created to analyze the potential effects of eradication of northern snakehead in two Arkansas counties. The report provides a brief history of snakehead introductions in North America, a review of collection and identification efforts in the Piney Creek basin, and proposed rapid response plans (i.e., chemical treatment with Rotenone ) to eliminate the threat of the invasive fish. National Management Plan for the Northern Snakehead (Channa argus) (2006) Northern Snakehead Working Group of the Aquatic Nuisance Species Task Force pdf In 2006 the U.S. Fish and Wildlife Service (USFWS) convened a Northern Snakehead Working Group (NSWG) to provide input on the development of a Snakehead Control and Management Plan (SCMP). This SCMP was developed with the input from members of the NSWG and other northern snakehead experts to guide the USFWS and other interested parties in managing existing populations and preventing the spread and introduction of this species into additional areas of the United States. Rapid Response Plan for the Northern Snakehead (Channa argus) in Massachusetts (2005) Prepared by ESR International for the Massachusetts Department of Conservation and Recreation This report outlines the morphology and ecology of the northern snakehead, and also proposes a rapid response plan for the state of Massachusetts that includes species detection, identification, and confirmation processes as well as potential post-capture quarantine, control, and outreach/education techniques. Risk Assessment for Northern Snakehead (Channa argus) in Canada (2005) Fisheries and Oceans Canada The Canadian federal government conducted a biological risk assessment to determine the risk of northern snakehead in Canada. This assessment included evaluating the risk of survival, reproduction and spread of these species, as well as their pathogens, parasites or fellow travelers (e.g. other invasive species) should northern snakehead be introduced into Canada. Snakeheads (Pisces, Channidae) - A Biological Synopsis and Risk Assessment (2004)

4 U.S. Geological Survey This report provides a comprehensive assessment of the risks involved with introductions of potentially invasive snakeheads into nonnative waters. U.S. and Canadian Federal Resources Northern Snakehead National Aquatic Nuisance Species Task Force Recognizing Northern Snakehead U.S. Fish and Wildlife Service Invasive Species Program: Snakeheads - The Newest Aquatic Invader U.S. Department of the Interior, U.S. Geological Survey, U.S. Fish and Wildlife Service Snakehead Fact Sheet U.S. Geological Survey-Nonindigenous Aquatic Species (database) Invasive Species Program Snakeheads, Aquatic Invaders U.S. Geological Survey-Florida Integrated Science Center Snakehead Species Profile U.S. Department of Agriculture-National Invasive Species Information Center Not Welcome in Canada: Preventing a Northern Snakehead invasion Department of Fisheries and Oceans Canada State and Provincial Resources Aquatic Invasive Species: Snakehead Indiana Department of Natural Resources Snakehead Fish Michigan Department of Natural Resources Northern Snakehead Fish (Channa argus) New York State Department of Environmental Conservation Northern Snakehead (Channa argus) Ontario Federation of Anglers and Hunters-Invading Species Awareness Program Northern Snakehead (Channa argus) Pennsylvania Sea Grant Northern Snakehead Watch Card Pennsylvania Sea Grant & Boat U.S. Foundation Northern Snakehead Pennsylvania Fish & Boat Commission

5 Fishing Wisconsin FAQ: Did I really catch a snakehead? Wisconsin Department of Natural Resources Mistaken for a Snakehead: The Bowfin Story Ohio Department of Natural Resources Norm the Chomper Northern Snakehead Sea Grant Nonindigenous Species (SGNIS)