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distance.
The bridge is green, not blue, but otherwise it could be the new local span across the Mississippi River from La Crescent, Minn., to La Crosse, Wis. But what dominates this U.S. Fish and Wildlife Service photograph from the Illinois River is a frantic field of glittering fish, boiling out of the water.
Within a decade, boaters in the area may see the same sight, wildlife officials warn.
Asian carp silver, bighead and grass are among 55 invasive aquatic animals and 12 plants known to have appeared in the upper Mississippi River, according to the U.S. Geological Survey.
But not since zebra mussels has an invasive species had the potential to so drastically change the river as the silver and bighead carp, said Pam Thiel, project leader at the La Crosse National Fish and Wildlife Conservation Office in Onalaska, Wis.
Late last week, the Minnesota Department of Natural Resources confirmed an angler recently caught a bighead carp in Lake Pepin, a section of the Mississippi River about 70 miles north of La Crosse. It was the second bighead carp taken from Lake Pepin.
And where the bighead goes, Thiel warned, the silver carp usually follows.
The silver’s tendency to leap at vibrations in the water turning a boat run on the Illinois River into a gantlet of flying fish that can slam into craft and human alike has made the carp both a media celebrity and “kind of the poster child of the new wave of invasive species,” Thiel said.
But what the carp do underwater alarms biologists almost as much, Thiel said.
Unlike the bottom-rooting common carp that has long been a Mississippi River resident, silver and bighead carp feed voraciously on microscopic plankton. That puts them in direct competition with young native game fish.
Researchers say the silver and bighead carp grow at a rate that would prompt testing if seen in a human athlete and to a size that means almost nothing else in the water can touch them: up to 60 pounds for the silver, more than 100 pounds for the bighead. They can reach maturity in two years, reproduce when 3 to 4 years old and are capable of producing tens of thousands of eggs.
In some parts of the Illinois River, Asian carp now make up 80 percent to 90 percent of the bulk of all organisms in the river, said Heidi Keuler, a fishery biologist for the U.S. Fish and Wildlife Service in La Crosse.
“They (anglers) want striped bass,” said Keuler, “and they pull up a bighead.”
In June, Keuler joined other wildlife staff and biologists in the sixth annual “carp corral,” a four-day survey of the carp population on 180 miles of the Illinois River.
What she saw was “scary,” she said: the number of carp her team counted had more than doubled from the previous year.
“You think about if they become that bad up here ... so many people recreate here on the river,” Keuler said.
In our midst
Asian carp are thought to have escaped into the Mississippi River from fish farms in the southern states, where they were imported in the 1970s to help water quality.
The Mississippi would seem to have a ready-made set of walls against the carps’ surge northward in its lock and dam system. Native skipjack herring, for example, were blocked from moving upriver when Lock and Dam 19 went up at Keokuk, Iowa, in 1913.
Ron Martin, aquatic invasive species coordinator for the Wisconsin Department of Natural Resources, thinks the Keokuk dam will hold back the Asian carp hoard as well.
“As it stands now,” Martin said, “that dam in southern Iowa is the key.”
But Thiel called the locks and dams a “swiss cheese barrier” for the Asian carp. Some already have navigated past Keokuk, locking through the way barges do, she said.
Bighead carp have been reported near Lansing, Iowa, and, as mentioned, in Lake Pepin.
“I don’t want to cause alarm, but there are some that are in our midst,” she said.
The Illinois River, too, has locks and dams, but that didn’t stop the fish from moving up the river to within 45 miles of Lake Michigan, Thiel said.
The federal Water Resources Development Act, recently sent to President Bush, includes money for a new electric barrier to replace one already installed on the Chicago Sanitary and Ship Canal to keep the carp out of the lake.
The act also is thought to have money for a “bubble barrier” at the Mississippi River’s Lock and Dam No. 10 near Guttenburg, Iowa, that would emit high-frequency sound waves underwater to drive the carp away, Thiel said.
She isn’t confident that would be effective, considering the river’s size and regular boat traffic.
Another fear is juvenile Asian carp look similar to some bait species, such as gizzard shad, and could mistakenly be introduced to other waterways, Keuler said.
Cold winters, which have kept some other invasives from spreading north in the past, also won’t hold Asian carp at bay, Thiel said. The species are native to waters that extend into Siberia.
No longer funny
Jeff Rach, research fisheries biologist at the U.S. Geological Survey’s Upper Midwest Environmental Sciences Center on French Island, has tested several toxic agents on the bighead and silver carp but found nothing that wouldn’t also kill every other fish in the water.
Rach worries the public and the government won’t take the threat seriously enough until the carp have arrived and settled in.
“Everybody watches the news and thinks, Hey, this (jumping fish) is kind of funny’ ... but if they do get here, it’s going to be a rude awakening, because it will change life on the river,” Rach said.
Getting federal action on invasive species has been a frustratingly slow process, one that doesn’t tend to kick in until the species are well established and almost impossible to eradicate, biologists say. For example, while silver carp have been seen in the river for more than two decades, it wasn’t until July that the federal government barred further importation and interstate transport of the species.
A better federal system and federal funding is needed to monitor for invasive species and react quickly to shut them down when they surface, Rach said.
“Once you don’t get at them right away, they spread out,” Rach said, “and then there’s no way to ever eliminate them.”
Thiel is hoping a federal bill introduced by Rep. Ron Kind of La Crosse the Refuge Ecology Protection, Assistance and Immediate Response Act will help in the fight.
The measure, now in committee, would provide grant money to remove invasive species from national wildlife refuges.
“The money isn’t there (now) for research,” Rach said. “There’s money there, but it isn’t proportionate to the problem.”
The invaders
Some of the top invasive threats to the Mississippi River and other area wetlands:
Asian carp: Could rival zebra mussels in potential to devastate the river ecosystem.
Zebra mussels: After showing signs of dying off a few years ago, zebra mussels are “back with a vengeance,” said Pam Thiel, project leader at the La Crosse National Fish and Wildlife Conservation Office in Onalaska, Wis. More worrisome, their numbers are increasing in areas to the north, such as Lake Pepin, that had few or no problems before.
Faucet snails: This European species and the small fluke trematode worms they harbor have been responsible since 2002 for killing thousands of waterfowl in the region during spring and fall migration. The birds, primarily coots and scaup, ingest the worms when they eat the snails.
Purple loosestrife: This pretty ornamental plant was used for landscaping for many years. But along rivers and streams, it forms dense, impenetrable growth for wildlife and crowds out native species. Cultivation of a special beetle that feeds on loosestrife has proven effective, said Eric Nelson of the U.S. Fish and Wildlife Service, but without more money, “we don’t have the staff to be working year in and year out.”
Reed canary grass: Both native and imported forms have completely overrun some areas.
VHS (and other pathogens):
Viral hemorrhagic septicemia, a disease that causes fish to bleed internally, was confirmed in Wisconsin this year after emerging in the eastern Great Lakes in 2003. It first surfaced in Europe; how it reached the Great Lakes is unknown.
Eurasian WATERmilfoil: This former aquarium plant is particularly tough to control because plant fragments can grow into a full plant.
What can the public do to prevent invasive species?
Clean boats before going between waterways. In particular, make sure no plants are clinging to the boat motor, hull or trailer.
Dispose of rather than release bait fish. Young Asian carp, for example, look very similar to some minnow species, said Pam Thiel, project leader at the La Crosse National Fish and Wildlife Conservation Office.
Avoid transferring water, such as from livewells or bait buckets, into different waterways.
Contact a wildlife management agency, such as the Upper Mississippi National Wildlife and Fish Refuge offices or the Department of Natural Resources in your state, if you see what you believe might be an invasive species.
Use native species when landscaping.
Don’t release pets into the wild.
Betsy Bloom can be reached at bbloom@lacrossetribune.com or (608) 791-8236.
