Recommendation: Poison The Pond

A panel of scientists recommended poisoning a pond that has become home to a breed of carnivorous Chinese fish to make sure the fish don't escape and spread through Maryland's waterways.

The 12-member panel agreed the state needs to take action to eradicate the northern snakehead, which grows to more than 3 feet long and feeds voraciously on other fish. Not doing anything would risk throwing the natural ecosystem off-kilter, they said.

"You're talking about a total rearrangement of the food chain when you introduce a top predator like this," said Walter Courtenay, an ichthyologist with the U.S. Geological Survey in Florida. "It definitely changes the neighborhood."

Officials from the Department of Natural Resources have caught more than 100 juvenile snakeheads in the 9-acre pond - apparently hatched this year and measuring up to 4 1/2 inches long.

The panel considered several ways to get rid of Maryland's snakehead, including physically removing them through trapping, netting, and electroshock stunning. However, those options would not ensure that every last fish is killed. The group also is thinking about draining and filtering the pond, although that poses logistical difficulties.

The most effective measure, the group tentatively said, was to treat the pond with rotenone, a nontoxic chemical extract from the roots of tropical plants, which enters the fish through the gills and disrupts the flow of oxygen. Rotenone degrades in 2 to 6 days and has no long-term effects on the water.

Some scientists were not positive that rotenone would be effective on snakeheads. Unlike most fish, the snakehead goes to the surface to gulp air through its mouth, as well as underwater with its gills, allowing it to survive out of water for up to three days under very moist conditions. The DNR will conduct rotenone tests next week.