I keep hearing about this snakehead fish that was found in Maryland and Virginia. What the heck is a snakehead? And should I be afraid?
-Bill Fox, Atlanta, Ga.

As an impressionable child, Bill, I happened upon a well-thumbed paperback copy of Bulfinch’s Mythology. This schoolhouse standard was harmless enough, with its heroic tales of Greek gods and goddesses, but some of the myths possessed a darker edge. Medusa, for example, with her dread snake locks, the mere sight of which turned men to stone. It was the story of Pandora’s box, though, that really scared the daylights out of me. Curiosity was Pandora’s sole tragic, yet very human, flaw. Instructed to never open a beautiful, beguiling trunk, Pandora nonetheless succumbed to temptation. As soon as she threw open the top, out poured a host of horrible imps, wicked fairies, and cruel sprites representing all the evils of humankind. Her curiosity had loosed pain and suffering upon the world and her futile attempts to right her wrong came to naught.

Invasive aquatic species such as the snakehead fish might seem like modern-day Medusas, but their presence in our waters is more like an opening assault from our own Pandora’s box. When, in 2002, a pond in suburban Maryland yielded previously unknown breeding populations of northern snakeheads, a species native to the Far East, the reaction was swift and, supposedly, complete-they were all destroyed. The story, breaking in the slow news of summer, received international attention. (Interestingly, around the same time, two non-breeding snakeheads were discovered in Lake Wylie, near Charlotte.) Now, two years later, at least five snakeheads have been caught in the Potomac River and its tributaries. Seemingly, despite our best efforts, the creature, nicknamed “Frankenfish,” had escaped into the wider area.

The northern snakehead has a frightful name and more than lives up to it by its ferocious nature. Native to China, Korea, and Russia, this species has a long, torpedo-shaped body and a mouthful of sharp, jutting teeth. It has a reputation as a voracious, top-tier predator that feeds on fish, frogs, birds, and small mammals. It can grow up to three feet long, and by using a primitive lung, has the disconcerting ability to travel short distances on land. With no natural predators in our waters, the snakehead could be bad news for both native and game fish species. Once a breeding population is established, the problem becomes one of control, or mitigation, rather than elimination. In other words, the snakehead could be here to stay.

In water’s dynamic medium, invasive species can spread with alarming ease. In the 1980s, zebra mussels, native to the Caspian Sea, arrived in the Great Lakes in the ballast water of commercial ships. Despite, or perhaps because of, their amazing water-filtering abilities, they turned native ecosystems into aquatic deserts, consuming the microscopic organisms needed by native fish and freshwater invertebrates. The extremely adaptable zebra mussels also attach themselves in thick clusters to pipes, intake valves, and turbines. The prolific bivalves have been found in the upper reaches of the Chesapeake Bay watershed. Closer to home, they have turned up on boating equipment in Virginia’s Smith Mountain Lake, and in 2002, an isolated quarry in Prince William County. In both instances the mussels were destroyed, but constant vigilance is still required. If the introduced aliens gain a foothold in Southwest Virginia watersheds, biologists fear the effect on rare native mussel species could be devastating.

In the 1990s, the lionfish, a strangely beautiful but venomous saltwater fish, was introduced along Florida’s Atlantic coast and has moved steadily northward. In March, a fisherman near Morehead City, N.C., caught the largest specimen yet seen on the East Coast. National Oceanographic and Atmospheric Administration (NOAA) scientists now believe that this voracious predator, native to the Pacific and Indian Oceans, is established and reproducing along the Southeast coast. Other creatures with exotic-sounding names such as the Vietnamese nuclear worm, MSX parasite, veined rapa whelk mollusk, European green crab, and Asian eel, are established, or in danger of becoming established in the Chesapeake Bay and along the East Coast.

The northern snakeheads recently captured in the Potomac River watershed have disturbing, if still uncertain, implications for our region. It’s unclear if the five individuals-all under sexually reproductive age-were part of a reproducing population or simply widely scattered aquarium escapees. Concerted attempts by Maryland and Virginia wildlife agencies have yet to turn up any more. The Smithsonian Institution is conducting DNA tests to determine whether the snakeheads are related to those caught in the Maryland pond two years ago. Meanwhile, anglers have been alerted as far west as West Virginia to be on the lookout for the fish, their young, or signs of nesting activity. The truth is, no one can predict exactly what would happen if the snakehead becomes established in the Potomac watershed. Could populations increase exponentially, wiping out native or more desirable fish? Or could the snakehead settle into a part of the ecosystem, its numbers kept to acceptable levels through aggressive management practices? No one knows.

What is certain is that invasive species, like the inhabitants of Pandora’s box, can inflict untold pain and damage to humans and animals alike. Fortunately, Pandora’s tale has something of a happy ending. After the last of the evil creatures had escaped, Pandora heard a faint voice calling to her to release it from the box. Reluctantly, she heeded the call, and it’s well that she did. That last spirit was a good one-hope-and instead of stinging her, it took up residence in her heart and remained there, giving us all the expectation of an optimistic future.

Editor's Note: At press time the number of northern snakeheads caught in the same stretch of the Potomac had increased to 14, including two egg-bearing females. Though officials haven't come to any conclusions yet, it appears increasingly likely that the individuals represent an established population.

Charlottesville’s William Cocke is always turning over rocks and rotten logs to see what’s underneath. As a young Boy Scout, he learned that cedar bark makes good tinder and four-of-a-kind beats a full house. He also remembers the Camp-o-ree where he had to kill a live chicken and cook it for dinner. He was not traumatized in the least and has no plans to sue. He can be reached at wtc4q@virginia.edu.