Dumping poison in a Crofton pond may be the best way to prevent a highly predatory exotic fish from escaping into nearby waterways, one of the country's leading experts said yesterday.
Walter Courtenay, a researcher with the U.S. Geological Survey in Florida, said most other options being considered can't ensure the eradication of the northern snakehead.
"It comes down to protecting fishing at an 8- to 9-acre recreational pond or preventing a snakehead ... from getting loose and reproducing," he said.
Last month, an angler caught an 18-inch snakehead -- a torpedo-shaped native of the Yangtze River region in China -- and tossed it back into the pond, sandwiched between Route 3 and the Little Patuxent River.
Federal experts reviewing a snapshot by the angler identified the fish last week, touching off a scramble by the state to corral it. A snakehead eats every other fish in sight, can live three days out of water and can walk short distances on extended fins to another body of water.
"Of the 28 species of snakehead, the northern snakehead is the most hardy and has the highest reproductive rate," Courtenay said. "They are voracious predators that can easily tolerate Maryland winters."
A fully grown female can produce 100,000 eggs each year; this is the breeding season. The fish can grow to 36 inches.
Department of Natural Resources biologists set traps on the pond bottom Friday but did not catch a snakehead. During an inspection Monday, they talked to a father and son fishing the pond who had unwittingly caught and released one.
"Is it the same one or a different one? We don't know for sure," said DNR spokesman John Surrick.
The state's options are dwindling. An attempt to shock the pond and bring stunned fish to the surface failed, and pumping out the water risks letting the fish escape to the river.
If biologists poison the pond, they will likely use Rotenone, a common insecticide used in animal dips that rapidly breaks down in soil and water.
Earlier suspicions that the fish might have come from a nearby pet shop that went out of business were discounted yesterday by Courtenay.
"This species of snakehead is not sold in the aquarium fish trade," he said. "It is sold in Asian specialty markets and in restaurants in D.C."
Courtenay speculates that someone purchased snakeheads for dinner and then changed his mind and dumped them in the pond.
While there are no federal restrictions on the importation of snakeheads, 13 states have banned them.
"Unfortunately for you," said Courtenay, "Maryland is not one of them."
