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Snakeheads: How Big of a Problem? - October 8, 2017

Northern snakeheads are an invasive species that pose a large threat to native species in all parts of Maryland due to their rapid reproduction capability and ability to adapt to different environments. They are major competitors for animals that thrive in Chesapeake Bay tributaries such as the Potomac and Wicomico River.

The Northern snakehead is native to Asia, but was first discovered in the United States in 1977 and made its mark in Maryland in 2002. A Crofton man decided to bring the fish alive from a New York market to his house hoping his sister would try the fish. When she refused, he kept them in a fish tank and later released them in a pond outside of his house. An angler fishing in the pond caught this unidentified fish and the picture was sent to the Maryland Department of Natural Resources. When another angler caught the same species in the same pond, news of the fish spread and newspapers described the snakehead as a viscous predator that can destroy an ecosystem. Some of the threats and qualities of the fish were overexaggerated in these news articles. They described the fish as able to travel long distances on the ground, but the Northern Snakehead species found in the Crofton pond could not. The real threat is in their ability to reproduce and live in harsh conditions that their competitors could not stand.

After the snakeheads were found in Crofton they were considered “injurious wildlife” through the Federal Lacey Act which prohibits import and interstate transport of snakeheads in Maryland. Unfortunately, that did not stop the spread of the species. In 2004, they were discovered in the Potomac River and have grown in population and expanded their territory to the bay tributaries on the Eastern Shore.

Females can lay tens of thousands of eggs each year and they tend to do so in wide shallow wetlands. This makes the possibility of extermination of the fish almost impossible. They have similar feeding habits as largemouth bass and yellow perch which are their competition in Chesapeake tributaries. The fish can adapt to many different ecosystems due to the ability of breathing atmospheric oxygen which gives them an advantage over native fish species. Snakeheads have sacs above their gills acting as lungs which allows them to draw oxygen from stored air. This enables them to survive out of the water for multiple days at a time and possibly outcompete their competitors. While the snakehead has not been proven to be the sole reason for a destroyed ecosystem, its unique capabilities make it a large concern in areas throughout Maryland. 

The Department of Natural Resources is taking control of the situation by monitoring the population of the species through tagging. DNR uses electrofishing to determine feeding habits, telemetry to track its behavior and angler surveys to verify its effects on recreational fishing. They also require that if you catch a snakehead outside of the Potomac that you kill it and report it to DNR so they can track the range of the species. You can identify the Northern snakehead by its long dorsal and anal fins, dark irregular blotches on its sides and its truncated tail.

Snakeheads have successfully established themselves in the Potomac River and have made their way across the bridge. They cannot handle salt water environments, so they could not have come directly across the Chesapeake Bay. It is suspected that the fish was illegally introduced in 2015 to a few neighborhood ponds in Wicomico and Queen Anne’s County. From there, the fish has made its way to the Patuxent, Nanticoke, Wicomico, and Blackwater rivers. There have been scattered sightings of snakeheads all along the Eastern Shore according to the United States Geological Survey. There was even one caught locally in the Saint Martin river about a month ago. Snakeheads pose a large threat to the ecosystem surrounding us and you can help by reporting them to DNR if you come across one. There is much more to learn about these fish and only time will tell what kind of damage they can do.

Holloway is an AmeriCorps member with the Maryland Coastal Bays Program. 



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