New evidence of Asian carp in Wisconsin waters

More news of asian carp spreading, further into Wisconsin

MADISON, WI – An angler’s catch of a bighead
carp in the Lower Wisconsin River and traces of silver carp DNA —
the carp known for its jumping behavior — in the St. Croix River
late last month have state officials calling on the federal
government to direct funding and attention to aquatic invasive
species in the Mississippi River system.

The two Asian carp species, which have been steadily moving
upstream, are among a growing list of invasive species threatening
Wisconsin waters of the Upper Mississippi River.

“High water levels on the Mississippi River are enabling more
Asian carp to move farther into Wisconsin waters,” says Bob
Wakeman, who coordinates Department of Natural Resources efforts to
prevent and control the spread of aquatic invasive species.

“Their presence is not a big surprise because their numbers have
grown tremendously in the lower Mississippi and Illinois river
systems and stray fish have reached Wisconsin before. But it’s a
big concern because of the potential damage they can do.

“We need the federal government to recognize the importance of
the Mississippi River basin’s invasive species problem and give it
the attention and funding it deserves.”

Wakeman says DNR also needs help from anglers and boaters to
keep these fish from getting established in the Upper Mississippi,
and in the Lower Wisconsin and St. Croix rivers, two of the most
pristine rivers in the country.

Anglers and boaters can help by continuing to follow state rules
to prevent the spread of invasive species continuing to follow
rules to prevent the spread of aquatic invasive species and the
fish disease VHS, and by reporting when they catch a bighead or
silver carp or the closely related grass carp and black carp,
Wakeman says.

“Please take a photo of it, note where you caught it, put it on
ice and bring it to a local DNR office,” he says. “We need
everybody’s help to keep our fishing strong and our rivers

Bighead and silver carp eat plankton and can potentially
decrease populations of native fish that rely on plankton for food,
including all larval fishes, some adult fishes, and native mussels.
Bighead carp can eat 20 percent of their own body weight in food
each day, and can grow to 60 inches and 110 pounds. Silver carp
also have been known to jump out of the water and injure

DNR is supporting Minnesota’s efforts to use electrofishing
boats and nets to look for fish below the St. Croix Falls dam,
where the silver carp DNA was detected earlier this month. Bighead
or silver carp have been captured in the Mississippi River along
Wisconsin’s western border since 1996 and a bighead carp was
captured at the mouth of the St. Croix River earlier this year.

The DNR also is partnering with the University of Notre Dame and
others to collect water samples to test for Asian carp DNA from the
Milwaukee, Kinnickinnic, Menomonee, Sheboygan, and Root rivers, and
the Milwaukee, Sheboygan, Racine and Kenosha harbors. The
Milwaukee, Kinnickinnic and Menomonee rivers were sampled last year
and no DNA from Asian carp was detected. The Great Lakes and
Mississippi River basins are artificially connected by the Chicago
waterway system.

No signs of Asian carp reproducing in Wisconsin

The silver lining to the recent findings is that no young Asian
carp nor other signs of successful reproduction have been
documented so far in any Wisconsin waters, says John Lyons, a
longtime DNR fisheries researcher and fish identification

Also, dams on the Wisconsin River at Prairie du Sac and on the
St. Croix National Scenic Riverway at St. Croix Falls will block
the fish from travelling farther inland, and measures already in
place can help slow the spread. [A fish passage planned for the
Prairie du Sac dam has been designed to prevent invasive aquatic
species and fish from getting further upstream.]

“The population densities are real low — the bighead and silver
carp entering the Upper Mississippi are mainly strays so there
really isn’t a critical mass up here yet,” Lyons says. “Will there
ever be? And what is the critical mass? It’s a big unknown.”

Wisconsin has taken actions within its own borders to slow the
spread of Asian carp and other invasive species, ranging from
banning the sale, transport, possession and introduction of
bighead, black, grass and silver carp, to enacting ballast water
treatment standards, to banning harvest of bait fish from the
Mississippi River and its tributaries. That’s important because
young Asian carp resemble gizzard shad and many minnows, and DNR
doesn’t want Asian carp to mistakenly be harvested and taken to
another water for use as bait, according to Ron Benjamin, longtime
DNR fisheries supervisor on the Upper Mississippi River.

Wisconsin also is supporting research to find ways of
eradicating aquatic invasive species or at least limiting their
ability to spread to other waters, and DNR has worked with other
states and federal agencies along the river to develop action plans
to slow the spread of carp and other invasive species.

Federal attention and funding, however, has shifted to the Great
Lakes region in recent years as concerns grew that Asian carp from
the Mississippi River system might invade the Great Lakes, Benjamin

While the Asian carp can be blocked from reaching the Great
Lakes by severing the connection between the two basins, options on
the Mississippi River are more limited, the DNR officials say. The
dams on the Upper Mississippi River itself are not high enough to
be complete barriers to the Asian carp moving upstream, and the
chance of closing down the locks, a decision that would need to be
authorized by the U.S. Congress, is very small, Lyons says.

Benjamin hopes the recent findings will help bring federal
attention back to the Mississippi River, noting that Asian carp
were brought to the United States by the aquaculture industry in
cooperation with federal agencies. “I hope that the recent finding
will refocus some attention and funding the Mississippi to help
implement a multi-state plan to prevent the introduction of new
aquatic invasive species within the basin, and to prevent those
already here from expanding into unconnected ecosystems,” he says.
“Finally, one of our best defenses is to keep our ecosystems
healthy and diverse.”


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