Fish Tales Carry a Bugging Effect By Angus PhillipsSunday, May 23, 2004; Page E13 Chicken Little, Chicken Little, the sky is falling. There's a snakehead in my soup. Or is it a cicada? Not since the great hydrilla scare 20 years ago has the Washington area been gripped by a natural crisis of such worrisome proportions. And two at once! Folks in Bethesda are putting up netting to protect their shade trees from the invasion of noisy insects, as if cicadas were somehow bad for trees, while Maryland officials earnestly tack wanted posters on docks along the Potomac deputizing anyone who catches a dreaded snakehead to kill it immediately by "cutting/bleeding or freezing." You remember hydrilla. It was the noxious, invasive submerged aquatic weed introduced into the river in the early 1980s by well-intentioned government officials hoping to restore plant life to the troubled waterway. It worked all too well as the weed spread like, well, a weed around the Wilson Bridge. The media went wild. Hydrilla, we were told, could choke the river from shore to shore in a mat so thick you could walk from Georgetown to Arlington. It would drive out native species and clog our water intakes. It was clingy and could drag unwitting swimmers and water skiers to untimely graves. The stuff was pure poison. It took a couple of years to discern that hydrilla was about the best thing to come along since dissolved oxygen. As it spread, it stabilized the river bottom, helping other native plants take root. Resulting stands of bright green vegetation clarified and oxygenated the water, provided habitat and food for fish and birds and turned the tidal Potomac below Washington into one of the best urban fishing and birding rivers in the world. I remember canoeing out of Belle Haven Marina when hydrilla was at its peak and staring over the side at a veritable underwater jungle, full of life. I was with a fellow who liked to hunt for carp with bow and arrow, and while he scanned the gin-clear water for his quarry I dreamily watched the underwater world drift by in little pockets of bluegills, minnows, bass and bugs. Sadly, the grass has since declined, though holdout patches remain. Meantime, government officials all across the Chesapeake watershed mourn the continuing loss of submerged vegetation and its onerous effects on aquatic life. Last year alone, we learned last week, 30 percent of tidal grass beds in Maryland died because of unusually high runoff from our polluted urban landscape during a rainy spring and summer. Now there is something to worry about. But snakeheads? Cicadas? Give me a break. For the record, the snakehead crisis to date centers on three, 12-inch-long fish caught in the Potomac this spring between Alexandria and Woodbridge. One may have been slightly larger but officials aren't sure because its head was hacked off by the nervous angler who caught it. Since Maryland officially owns the Potomac, it is stuck with the snakehead problem. Steve Early, assistant director of the state's Fisheries Service, is the point man and has been busy answering questions and posting posters. Kill, kill, kill, say the posters. "We don't want any live ones floating around," says Early. He's worried because the last time northern snakeheads turned up in Maryland, it was in a pond in Crofton where someone deposited a pair purchased at a live seafood market in New York. The pair did the snakehead thing and started making babies, and by the time officials drained the pond two years later there were seven adults and more than 1,000 juveniles. Snakeheads, said Early, had become the dominant fish in the pond, outnumbering bass, crappies and bluegills. "In the Potomac, we have an outstanding largemouth bass fishery with significant economic impact," he said. "I think we should be concerned about this fish because of the potential effect on species in the river that we are used to and enjoy." But Early admits snakehead hysteria may be out of proportion. In Asia, northern snakeheads are considered a delicacy. What's wrong with adding a little diversity to the river, I asked, especially if it involves something you can catch and take home and eat? Early laughed and said that in Japan, where largemouth bass are being introduced in some waterways, people are worried that they will adversely affect the snakehead population. In any event, he was willing to debunk a few myths about northern snakeheads. They look more like fish than snakes, he said, generally grow to a maximum size of about 30 inches and have regular fish teeth like a great northern pike. There's no evidence they will attack humans, except perhaps to protect their spawning nests. They do not walk on land but can wriggle around a bit, and they can live a few hours out of water, as can eels, crabs, bull minnows, catfish and a few other species. They do not tolerate salt or brackish water. Snakeheads are particularly well adapted to water where oxygen is scarce because they are able to breathe air. That might come in handy in places like the Potomac, where dead zones with no oxygen grow larger annually as humans dump more and more oxygen-eating nutrients into the rivers and streams. Early says while he's concerned about reigning in any threat from snakeheads in the Potomac, he's more concerned about other introduced species that do real, immediate damage to the environment, like nutria eating up tidal marshes on the Eastern Shore and mute swans uprooting vegetation. I mentioned another species his agency might want to focus on that's doing heinous things to all of earth's most vital resources -- land, water and air. Man.
In Search for Snakehead, Other Fish Get a Jolt By Joshua PartlowWashington Post Staff WriterSunday, May 30, 2004; Page C07 The fishing boat crept through the warm green water, past sprigs of hydrilla and milfoil, into a lush shoreline nook of the Pohick Bay. The depth finder ticked down -- four, three, two feet. A metal claw hung out from the bow, trailing its stainless steel tendrils in the slack water. Two men looked into the murk, holding their nets, poised to pounce. "If I were a snakehead, this would be a perfect spot," said John Odenkirk, a Virginia fisheries biologist. "A little cove, a lot of grasses. It's protected." He stepped on a pedal and sent six amps of electricity pulsing through the steel wires into the water. Stunned fish suddenly rose to the water's surface. White perch, long-nosed gar and common carp, among others, flopped onto their sides or floated belly-up, easy prey for the nets. In all, more than 200 fish of 21 species were scooped up in nets, measured and tossed back into the tidal waters of the Potomac River one morning last week. None was a snakehead. The electro-fishing technique, used for years to survey fish populations in lakes and rivers, is now being used to search the Potomac and its tributaries for the northern snakehead, the notorious Asian import that can breathe air, wriggle over land and devour scores of native fish. The four northern snakeheads found in the Potomac and its tributaries in the past few weeks have raised concerns that the predatory fish could disrupt the ecosystem and harm fish populations in the river. Scientists are intent on finding out whether there is a reproducing population or simply a limited number of individuals. "Right now, it's just pretty much poking around blind," said Steve Early, an assistant director at the Maryland Department of Natural Resources. "The biologist part of me says . . . 'There's got to be more.' I want to find out as quickly as I can." Maryland and Virginia officials plan to deploy gill nets and haul seines on the Potomac starting this week to assess the snakehead population, as well as continue electro-fishing surveys. The nonlethal shocking method, which runs off a 5,000-watt generator in Odenkirk's boat, is intended to temporarily immobilize the fish's muscles, to "maximize capture efficiency and minimize injury," he said. It is a powerful enough jolt that one of his colleagues was nearly knocked out cold a few years ago by an accidental blast of electricity as he stood near the boat. "He got laid out flat. He was stiff as a fish," he said. The hunt for snakeheads last week focused on the shallow shoreline waters of the bay and nearby Pohick Creek, within a mile of Little Hunting Creek, where the first Potomac snakehead was caught May 7. Scientists believe the fish prefers shallow water amid shoreline vegetation. In its native China, the snakehead is believed to prepare its nest by clearing a circular area in the grasses about one meter in diameter, then building a cone-shaped structure and laying its eggs on top, said Steve Owens, a fisheries biologist who accompanied Odenkirk on the electro-fishing outing. "But there's not a lot of information out there that pertains to the Western Hemisphere," he said. "We're assuming that's how they would interact with the environment here, but we really don't know."The lack of knowledge about the snakehead, or what it could do to the Potomac habitat, prompted a sense of alarm that some officials say may be unwarranted. In South Florida, where the bull's-eye snakehead was found four years ago, surveys of fish populations show that the intruder did not wipe out native species, said Paul Shafland, director of the nonnative fish research laboratory of the Florida Fish and Wildlife Conservation Commission. "There's no evidence that [snakeheads] decimate fish communities and then walk to another fish population," he said. "Are they problematic? Most certainly . . . but they're more of an unknown entity. And the fact that the impact is unknown does not mean it's inherently satanic." Odenkirk, who works for the Virginia Department of Game and Inland Fisheries, described the local reaction to the arrival of snakeheads as "hysteria." Since environmental authorities canvassed marinas and public boat launches along the river this month telling fishermen to report any snakeheads they might find, they have been inundated with calls from anglers. Usually the suspected snakehead turns out to be hake or lamprey. Odenkirk recently drove to meet one man who was convinced he had snagged the real thing. "I took one look inside the brown paper bag and walked away. I told him, 'It's an eel,' and he just started crying," he said. "It's crazy." In the Potomac, many nonnative species of fish and plants have established populations. A frequent sighting on Wednesday's trip was the common carp, a large exotic fish cultivated in Europe and Asia that was intentionally introduced in North American waters in the 19th century to be a sport fish. The channel catfish, blue catfish and, most recently, the flathead catfish have also infiltrated the Potomac. Odenkirk said they are changing the population makeup of local waters, but some fishermen enjoy the opportunity to hook a 50-pound fish. Even the hydrilla, the rapidly growing invasive aquatic weed that sparked widespread concern in the early 1980s, turned out to have some ecological benefits, he said, including preventing erosion, cleaning the water and providing habitat for fish and waterfowl. "The snakeheads are disconcerting, but I'm not ready to push the panic button," he said. "And I hear they're good to eat." Nevertheless, the campaign to determine the extent of the snakehead's presence in the Potomac is moving forward quickly. A snakehead task force has been established to coordinate efforts between state and federal authorities. And fishermen are doing their part, finding more snakeheads than the scientists have turned up. On Thursday, in the same spot the electro-fishing boat patrolled a day earlier, a commercial fisherman snagged a northern snakehead, the fourth specimen caught in an eight-mile stretch of the Potomac within the past month. © 2004 The Washington Post Company
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Topic: Northern Snakeheads found in Maryland/Virginia waters (Read 8158 times)
