National Invasive Species Awareness Week: Northern snakehead fish
Learn more about the northern snakehead fish, an aquatic invasive species in Michigan, and what you can do about it.
National Invasive Species Week 2015 is February 22-28. Invasive species are plants, animals and other organisms that are not traditionally found in a given location (in this case the Great Lakes) and create a negative impact of some kind, whether ecological, economic, social and/or a public health threat.
To help celebrate, Michigan State University Extension is featuring a different aquatic invasive species that has invaded or has the potential to invade Michigan’s environment each day this week. Today’s featured aquatic invasive species is the northern snakehead fish.
Species Name: Northern snakehead (Channaargus)
Description: According to the Great Lakes Commission, this aquatic invasive species 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. Young northern snakeheads are typically golden brown to pale grey, changing with age to a darker brown with dark brown or black blotches.
Similar species: Mudpuppies, burbot, bowfin and longnose gar are all similarly colored to the northern snakehead fish which is why people should be on the lookout for other characteristics that distinguish snakeheads from these similar species. Mudpuppies have legs rather than fins because they are amphibians, not fish. Burbot have a barbel (like catfish) on the lower jaw. Bowfin have short anal fins, while snakehead anal fins are nearly half the length of the body. As the name implies, longnose gar have a long nose that is narrow with nostrils on the end. Michigan Out-of-Doors has a video explaining how to identify northern snakehead compared to the bowfin.
Origin: The northern snakehead is native to China, Russia and Korea.
How it came to the Great Lakes: Breeding populations of the northern snakehead have not yet been found in the Great Lakes; however, there are established populations as close as nearby drainage areas in New York and Pennsylvania. With populations now present in other parts of the United States, introduction into the Great Lakes is also possible through man-made connecting waterways and boating practices which allow water transfer from infected waterways to uninfected ones.
How long it has been here: No breeding populations have been found in the Great Lakes, although a live individual was found in Lake Michigan in downtown Chicago in 2004.
Extent of range: Breeding populations are found in the eastern United States and individuals have been found as far west as California.
Why it is a problem: The Great Lakes Commission states that 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, 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 sport fish. As is the case with other invasive fish, there is concern over the snakehead’s potential to transfer harmful pathogens to native fish populations.
How it is spread: Northern snakehead can be spread through a number of possible vectors including natural movement between water bodies, sales at live fish markets, boating practices, ceremonial release as prayer species, and disposal of unwanted aquarium fish.
A cool/unusual fact: Northern snakehead can “walk” on their pectoral fins and survive out of water for extended periods of time allowing them to move from one water body to another. They are also sometimes referred to as Frankenfish.
Management actions/options: Control and eradication can be difficult. Once a large breeding population is established, eradication is nearly impossible. Successful eradication has been done with a chemical called Rotenone when dealing with individuals and small populations. Early detection and rapid response can lead to more effective control.
In October 2002, the U.S. Fish & Wildlife Service included northern snakehead as injurious wildlife under the Lacey Act, which means that importation and interstate transportation is now prohibited. Several Great Lakes states, including Michigan have passed legislation making it illegal to possess live snakehead.
What you can do to help prevent the spread:
Report it: If you catch this fish in Michigan, do not put it back in the water and call the nearest Department of Natural Resources Operations Service Center.
Practice the Clean, Drain and Dry method for watercraft prior to moving them between lakes.
Invasive Species Resources:
- Northern snakehead fact sheet
- Michigan Invasive Species Information Network smartphone app
- Michigan Natural Features Inventory publications
- Michigan Natural Features Inventory field guide
- Great Lakes Aquatic Nonindigenous Species Information System
- Michigan Department of Natural Resources - Invasive Species