CROFTON, Md. — Tests show that a breeding population of the voracious northern snakehead fish has been wiped out and state wildlife officials have started rehabilitating the pond where the alien invaders were found.
Biologists have found the bodies of six adult snakeheads and more than 1,000 juveniles since they sprayed the fish poison rotenone on the 4-acre pond here about two weeks ago. The fish were descendants of one pair put into the pond two years ago by a man who bought them in New York.
Electroshock tests showed there were no live fish remaining in the pond, the Maryland Department of Natural Resource said Wednesday.
The rotenone was expected to decompose quickly, but rainy weather lowered the pond's temperature and slowed the process.
DNR spokesman John Surrick said there was no indication that any snakeheads, natives of China, had escaped from the pond and gotten into the Little Patuxent River--which is just 75 yards away--or two adjacent smaller ponds that also were poisoned.
The extreme measures were necessary because scientists feared that snakeheads, which can wriggle short distances on land, could spread and devastate the state's ecosystem. Snakeheads can reach 3 feet in length and they devour smaller fish.