Relief in Chicago: No More 'Frankenfish'

Phil Willink from Chicago's Field Museum holds a northern snakehead fish from China during a press conference at Chicago's Burnham Harbor, Tuesday, Oct. 19, 2004. Biologists set large nets into the harbor Monday in search of a snakehead, like the one shown, after one of the species was caught in the harbor last week. The northern snakehead, so-called "Frankenfish," is a type of fish known for its voracious appetite and ability to wreak havoc on freshwater ecosystems. No snakeheads were found in the nets, bolstering a theory that the snakehead caught was simply dumped out of an aquarium by someone who didn't know what else to do with it. (AP Photo/Nam Y. Huh)

CHICAGO (AP) -- An anxious search Tuesday of a Chicago harbor turned up no more northern snakeheads, a voracious alien fish that can devastate freshwater ecosystems by gobbling up food and native fish.

"This is a good sign that we didn't catch any," said Philip Willink, a fish biologist with Chicago's Field Museum who checked six traps and nets in Burnham Harbor.

An angler caught an 18-inch northern snakehead in the harbor about 10 days ago, raising fears the species might spread into Lake Michigan.

Willink speculated that the lone fish came from an aquarium and was dumped by someone who got tired of feeding it and didn't want to kill it.

But Willink said experts from the museum and the Army Corps of Engineers will continue to scour the lake at least through the end of the week.

The northern snakehead, which is native to China, Korea and Russia, has been dubbed the "Frankenfish" for its ability to breath air and wriggle short distances over land in search of ponds and lakes to invade.

Willink said when the fish are small they devour food that native fish need to survive. Then as they grow to more than 3 feet long, they eat other fish.

"Whatever fits in their mouth, they'll eat," he said.

Snakeheads first drew attention a couple of years ago when two were discovered in a Maryland pond. They've also been spotted in Washington, California, Texas, Alabama, Florida, Hawaii, North Carolina, Virginia, Rhode Island, Massachusetts and Maine.

It is illegal to bring live northern snakeheads into the country.