Posted on Thu, Oct. 14, 2004
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'Frankenfish' fear spreads to Midwest
A northern snakehead found in Lake Michigan
BY DENNIS LIEN
Pioneer Press
A northern snakehead, the invasive fish that's become established in the
Potomac River and threatens that region's aquatic ecosystem, apparently
has been netted in a Chicago harbor of Lake Michigan.
While there's no indication other snakeheads are in the harbor, scientists
fear their potential impact on Midwestern lakes and rivers, including
those in Minnesota and Wisconsin. The fish can survive several days out of
water if kept wet, and they can be impossible to eradicate. Its damage
potential is so unnerving, the creature is sometimes called "Frankenfish."
"I'm hoping ? I've got my fingers crossed ? that this is the only northern
snakehead in Lake Michigan,'' said Walter Courtenay Jr., a research
fishery biologist with the U.S. Geological Survey and an expert on
northern snakeheads.
Courtenay said a fish that Matthew Philbin of Tinley Park, Ill., said he
netted in Burnham Harbor Saturday is definitely a northern snakehead.
Philbin took several pictures of the fish and posted the images on a local
fishing Web site to find out what it was. Courtenay, based in Gainesville,
Fla., eventually saw those images.
Philbin said Wednesday he has contacted the Illinois Department of Natural
Resources and was told it would pick up the fish Thursday. "It's in a
bucket in my garage freezer at the moment,'' Philbin said.
A spokesman for the Illinois DNR said the agency is anxious to see the
fish and to determine whether it is a northern snakehead.
"If this turns out to be one, we are going to have to figure out what to
do next,'' the Illinois DNR's Joe Bauer said. "It would not be good at
all.''
Natives of China, Russia and Korea, northern snakeheads are voracious
predators that can grow to 3 feet long. Two years ago, a pair was
discovered in a pond in Crofton, Md., along with thousands of young. The
pond was poisoned to kill the fish.
But this summer, anglers have caught 19 adult snakeheads in the Potomac
and its tributaries. Recently, a baby snakehead was caught, proving the
fish are breeding in the river.
Scientists said that meant the snakehead will be nearly impossible to
eradicate, even threatening the Potomac's plentiful bass population.
Juvenile snakeheads eat zooplankton and small crustaceans and adults eat
other fishes, crustaceans, frogs, small reptiles, and sometimes small
birds and mammals.
A reproducing population of northern snakeheads also has been found in a
Philadelphia pond that flows into the Schuylkill and Delaware rivers.
The fish are believed to have been imported here as food for the Asian
market and then dumped.
Philbin said he netted the snakehead while fishing for salmon at Burnham
Harbor, which is near downtown Chicago and is connected to Lake Michigan.
He said he was on a wall that surrounds the harbor when he saw the fish.
"I was 7 or 8 feet above the water when this fish swam up toward the wall
where I was fishing,'' Philbin said. "I honestly thought it was a northern
pike. ? I was curious to see it, so I netted it. If it had been a northern
pike, I would have put it back. But once I got it on shore, that's clearly
not what it was.''
Philbin said he thought immediately that the fish looked "really bizarre''
but added he'd never heard of a northern snakehead. He brought it home,
took pictures of it and posted the images on a fishing Web site. He got
plenty of feedback.
"I said, 'Check out this fish. What is it?' It got the attention of a lot
of people.''
Courtenay said the fish, which is about 18 inches long, probably is about
3 years old. While it's possible it's the only snakehead in the harbor, he
conceded that may not be the case.
"Based on past history, the probability of finding another is pretty
high,'' Courtenay said. "But I hope I am wrong.''
SNAKEHEAD AT A GLANCE
Identification: Maximum size exceeds 33 inches. Females release 1,300 to
15,000 eggs each spawn, which can occur up to five times a year. An
obligate air breather, it can live in oxygen-depleted waters by gulping
air at the water's surface and can survive several days out of water if
kept wet.
Native range: China, Russia, and Korea.
Habitat: Prefers stagnant shallow ponds, swamps and slow streams with mud
or vegetated substrate, and can endure cold temperatures.
Why they are bad: They displace native fish species and devour other fish,
crustaceans, frogs and small reptiles.
Dennis Lien can be reached at dlien@pioneerpress.com or 651-228-5588.
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