Aquatic biologists from the Field Museum and federal wildlife experts sent electric charges into Chicago's Burnham Harbor Friday after confirmation of the discovery of a dreaded snakehead hours before.
Fisherman Matt Philbin netted the 18-inch Asian carp Saturday and posted a picture of the invasive species on an Internet site. Scientists say northern snakeheads, which are native to China, Russia and Korea, have the potential to wreak havoc on the freshwater ecosystem, endangering the Great Lakes' $4.5 billion fishing industry.
The aggressive, canine-toothed species eats anything in its path, can survive in oxygen-depleted waters and could devastate native populations of salmon, rock bass, walleye, bluegills, northern pike and perch.
"Any new species can pose a problem and disrupt the ecological balance," Tom Trudeau, head of the Illinois Department of Natural Resources Lake Michigan Project, told WGN-TV. "It's another predator in the lake. If it becomes a predator in large numbers, it's going to compete with bass and other predators."
State conservation officials hope the snakehead is a loner that was dumped into the lake by someone who may have bought it for an aquarium and got rid of it when it grew too large. The northern snakehead is at home in the Great Lakes. It eats birds, frogs and small mammals, can survive cold winters and can even live for days out of the water if kept wet.
The U.S. Army Corps of Engineers used a device to send electric shocks into the waters of Burnham Harbor to temporarily stun fish, causing them to float to the surface for inspection. If more snakeheads turn up, authorities plan to drag the harbor with nets.
Army engineers are scheduled to begin construction of a $9.1 million electrified fish barrier in the Chicago Ship and Sanitary Waterway in two weeks to keep voracious Asian Bighead carp out of the Great Lakes. The electrified barrier resembling two railroad tracks 200 feet apart will replace an experimental temporary barrier near Lockport, Ill., that is nearing the end of its useful life.
"The immediate construction of an effective barrier on the Chicago Sanitary and Ship Canal is imperative if we want to protect the Great Lakes from Asian carp," former Chicago Alderman Bernard Hansen, chairman of the Great Lakes Fishery Commission's U.S. Section, said at groundbreaking ceremonies for the barrier near Romeoville, Ill., Wednesday. "These Asian carp are swimming toward Lake Michigan as we speak; we must have a way to stop them. Although the carp are still several miles downstream from the site of this new barrier, construction cannot happen fast enough."
Two species -- Asian Bighead carp and silver carp -- escaped into the Mississippi River watershed in the 1990s when aquaculture hatcheries in Arkansas were flooded. They made their way upstream, establishing themselves in scattered bodies of water. Bighead carp currently are in the Illinois River within 50 miles of Lake Michigan.
Bighead carp can reach 4 feet in length, weigh more than 100 pounds and consume up to 40 percent of their body weight daily. They are jumpers and often leap into boats on the river.
Snakeheads grow up to 15 pounds and reach 40 inches long. The federal government banned importation of snakeheads in October 2002, but they remain available on the Internet and have been sold live at Asian food markets.
Biologists say snakeheads could be just as devastating in depleting the food supply of native fish as Bighead carp.
''It is a nightmare scenario for the Great Lakes," Dennis L. Schornack, U.S. chairman of the International Joint Commission, an agency that monitors waterways connecting the United States and Canada, told the Columbus (Ohio) Dispatch. ''They would take out the entire bottom of the food chain that all commercial and sports fishing depends on."
The National Wildlife Federation fears if they breed the species could turn the Great Lakes into a huge carp pond.
A stray snakehead was found in Wisconsin's Rock River last year.
Snakehead surfaced in California in 1997, were found in Florida in 2000 and reached Maryland in 2002.
Authorities poisoned a pond in Crofton, Md., in 2002 when two adult snakeheads and thousands of young were discovered.
Fishermen caught 19 snakeheads on a 14-mile stretch of the Potomac River and its tributaries south of Washington this summer, and biologists said they are reproducing in the river.
A 3-inch juvenile, called a fingerling, was found near a boat pulled out of Dogue Creek in Fairfax County near Fort Belvoir two weeks ago. Several fish were egg-bearing females, the Virginia Department of Game and Inland Fisheries said.
Virginia authorities asked anglers not to release any suspect fish they catch.
Females spawn five times a year releasing thousands of eggs, and once the fish is established it is practically impossible to eradicate.
The snakehead prefers shallow, weedy ponds and slow streams with mud but would have little trouble finding habitat in the Great Lakes.
It is illegal to possess live snakeheads in 38 states.
No snakeheads have been found in the wild in Nebraska, and fisheries officials don't want one to be released. The state Game and Parks Commission has proposed regulations to ban the fish and get people who have snakeheads to surrender them before Jan. 1, 2006.
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