TRAVERSE CITY, Mich. (AP) - A water sample from Lake Michiganís Sturgeon Bay
in Wisconsin has tested positive for DNA from invasive Asian carp, although
itís unknown whether the genetic material came from a live fish, scientists
Itís the second positive DNA hit for the feared carp detected in Lake
Michigan in recent years, as experts work to determine how far the voracious
fish have advanced toward the Great Lakes. A water sample taken in 2010 from
the lakeís Calumet Harbor also yielded a positive result.
Four types of Asian carp imported decades ago have escaped into the wild and
migrated northward in the Mississippi River and many of its tributaries. Of
particular concern are bighead and silver carp, which gobble huge amounts of
plankton - microscopic plants and animals that are essential for aquatic
food chains. Scientists fear if they reach the Great Lakes, they could
out-compete native species and threaten a fishing industry valued at $7
An electric barrier in a shipping canal 37 miles from Chicago is meant to
block their path toward Lake Michigan. Just one live Asian carp has been
found beyond that point, although numerous DNA samples have turned up past
the barrier and in Lake Erie.
Scientists say fish DNA is found in mucus, scales and bodily wastes they
discharge. But some say there could be other sources, such as droppings of
birds that have eaten the fish, so it isnít certain that the Sturgeon Bay
discovery signals the presence of live Asian carp, much less a breeding
"Itís hard to know what to make of it,Ē said Mike Staggs, director of
fisheries management with the Wisconsin Department of Natural Resources.
The samples were collected and analyzed by researchers with the University
of Notre Dame, Central Michigan University and The Nature Conservancy as
part of a broader Great Lakes fish survey. Fifty samples were taken from
Sturgeon Bay in May, but the finding that one carried silver carp DNA was
confirmed only last week.
The Wisconsin DNR and the U.S. Fish and Wildlife Service will take more
samples from the area in hopes of determining whether the positive hit was a
fluke or something worse.
ďOne sample is a smoke detector,Ē said Chris Jerde, a Notre Dame biologist.
ďA couple of more samples is a fire.Ē
Itís too early to be alarmed, but the finding is ďan interesting development
that we need to research further,Ē said Brian Elkington, a deputy supervisor
with the Fish and Wildlife Service regional office in Minneapolis.
Sen. Debbie Stabenow, a Michigan Democrat, said the result underscores the
need for the U.S. Army Corps of Engineers to expedite proposals for
permanently shielding the Great Lakes from Asian carp. The Corps is wrapping
up a report scheduled for release early next year.
ďThese fish could destroy the Great Lakes ecosystem, as well as boating and
fishing industries and hundreds of thousands of jobs,Ē Stabenow said.