For the past decade, the U.S. Army Corps of Engineers and state departments of natural resources — especially those near the Great Lakes — have focused their efforts on controlling the migration of Asian Carp, a known invasive species, before it reaches the Great Lakes. It’s been a challenge.
The Army Corps of Engineers spends about $145 million a year to control and restore damage caused by invasive species, a figure that is escalating with the spread of existing species and the introduction of new invasive species. Effective invasive species education and prevention programs can help mitigate the spread of new invasive species like the snakehead, an air-breathing freshwater fish not native to North America.
The toothy northern snakehead has been found in Maryland ponds and the waters of the Potomac River near the District of Columbia since 2004. Unfortunately, the population of the voracious fish, which can live out of water for four days and use their fins and body to move over land especially when the ground is wet, is escalating. Snakeheads also have been found in California, Maine, Wisconsin, Massachusetts, Rhode Island, Hawaii, Florida and New York.
The fish, normally about 30 inches at maturity with the potential to grow up to 6 feet in length, threaten native fish, mussels, aquatic invertebrates, the fishing industry and the aquatic ecosystem. Native to Asia and Africa, the fish has not yet been detected in lakes managed by the Army Corps of Engineers, but its ever increasing population is causing concern.
The northern snakehead is known to disrupt the balance of the food chain and given habitat, has the potential to transfer pathogens to native species and other organisms, and can alter the flow of water, impacting recreation, navigation, associated wildlife and water quality. Because the snakehead has a voracious appetite and is not selective about what it eats, researchers and natural resource officials fear for critical habitats, endangered species and the health of game fishes at recreational sites, which often generate millions of dollars a year to a local economy.
One of the biggest problems with the fish is it has no natural predators in the U.S. and can spawn multiple times a year. It has a large mouth with razor sharp teeth, enlarged scales on the top of the head, eyes located far forward and scale patterns, head shape and eye position similar to a snake.
Natural resources managers and wildlife officials successfully advocated having the U.S. Fish and Wildlife Service add the snakehead family of fishes to the list of injurious wildlife under the Lacey Act, which states the fish cannot be imported into the U.S. or transported across states lines without a permit. It is also illegal to possess a live snakehead in Alabama, California, Florida, Maryland, Texas, Virginia and Washington. Several additional states also are considering making ownership illegal.
People who spot a snakehead or catch one should freeze it or put it on ice and immediately notify the nearest fish and game agency. Fishermen are asked to track the location of where the snakehead is spotted, as well as the size and number. Officials stress that fishermen should not release the fish back into the water or throw it on the bank.
For more information on Army Corps of Engineers efforts to control invasive species, visit http://go.usa.gov/87NW.
Editor’s note: The Maryland Department of Natural Resources provided information for this article.