The surest way to keep rampaging Asian carp from gaining a foothold in the Great Lakes is to sever the link between Lake Michigan and the Mississippi River basin, created by engineers in Chicago more than a century ago.
That would thrill environmentalists and those who make their living in the $7 billion Great Lakes fishing industry, which could be devastated by a carp invasion. Not so the barge operators who move millions of tons of commodities on the Chicago-area waterways each year.
And so, pulled in different directions by both, as well as politicians in the Great Lakes states, the Obama administration this week proposed a $78.5 million plan that appears to make no one happy.
"It appears to be politically negotiated rather than scientifically based ... sort of like trying to cut the baby in half," said Thom Cmar, an attorney with the Natural Resources Defense Council. "It offers a lot of middle-ground alternatives with no discussion of why any of them would actually work."
Shippers worry about a promised study that would examine closing more often a pair of navigational locks at Chicago, and the prospect that a long-term study could recommend severing the connection between the river and the lakes for good.
Environmentalists, meanwhile, fear the plan's reliance on strengthening an electric barrier designed to block the carp's advance — and other measures, such as stepping up efforts to find and kill fish that may have slipped through — is an expensive gamble that might not be enough to ward off an infestation.
"We're spending close to $80 million just for a short-term deterrent," said Joel Brammeier, president of the Alliance for the Great Lakes, an environmental group. "We need to stop pushing money toward temporary solutions and get everyone on track toward investing in one that works for good — and that means absolute physical separation."
Bighead and silver carp — both native to Asia — have been migrating toward the lakes since escaping from Deep South fish ponds and sewage treatment plants in the 1970s. The biggest can reach 100 pounds and 4 feet long, consuming up to 40 percent of their body weight daily in plankton, the base of the aquatic food chain. Once established in the lakes, the carp could starve out the prey fish on which popular species such as salmon and whitefish depend.
The carp have already infested parts of the Mississippi and Illinois rivers, driving away many native fish. Silver carp are known to hurtle from the water at the sound of passing motors and slam into boaters with bone-breaking force.
While scientists differ on whether the carp would thrive in the Great Lakes, which are colder, deeper and ecologically different than rivers, many say the risk is too great to take any chances.
"None of us know for certain what their impact would be," University of Notre Dame biologist David Lodge told a House subcommittee this week. "There's only one way to find out, and I don't think any of us want that."
To be fair, the solution environmentalists prefer — cutting ties between the lakes and the Mississippi — would mean reconfiguring some 70 miles of canals and rivers. That's a massive undertaking that could not happen quickly. "We cannot fight biology with engineering alone," Cameron Davis, the Environmental Protection Agency's spokesman on the issue, told the congressional panel.
Yet the federal plan is heavy on technological innovations. Among them: barriers using sound, strobe lights and bubble curtains to repel carp and biological controls to prevent them from reproducing. They're promising measures, but still on the drawing board.
Environmentalists and Great Lakes governors outside of Illinois who want to close the Chicago locks claim it's the best short-term option. But it isn't a foolproof solution, as young carp might still be able to slip through the leaky structures. The Chicago waterways also have other access points to Lake Michigan.
Army Corps of Engineers officials are putting their faith in the two-tiered electric barrier in the Chicago Sanitary and Ship Canal about 25 miles from Lake Michigan, to which they will add a third section this year. It emits pulses to scare off the carp or knock them unconscious if they don't turn back. No carp have been found above the barrier, although biologists have detected their DNA in numerous spots past it and even within the lake itself.
"While we're all talking," Lodge said, "the fish are swimming."
That almost certainly means at least some carp have eluded the device and reached the lake. The government's plan aims to keep their number low enough to prevent them from breeding. The problem is that no one knows how many carp need to make it into the lake to establish a foothold that can't be turned back.
"This is a lot of money to pile into stopgap measures," said Phil Moy, a University of Wisconsin Sea Grant researcher. "It may do some good in the short term, but in the long term it's not going to solve the problem of invasive species on both sides of the divide. Ecological separation has to happen for this to be successful."
AP Environmental Writer John Flesher has covered the Great Lakes since 1989.
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