Art Hackett:
We move now from the economy to the environment. This week, 350 biologists from the US and Canada, army engineers and coast guard personnel have been on a $33 million fishing expedition on the Chicago Sanitary and Ship Canal. That's how much it costs to determine if the invasive species known as Asian carp had been found near Chicago at Lake Michigan's doorstep. We'll have an update from the riverbank in a moment, but first here's the background on this costly fish story from one of our reporters, Andy Soth.

Any Soth:
The Chicago River flows backwards. Civil engineers reversed its flow and connected it by canal to the Mississippi River system around the turn of the 20th century. Today, that link is causing a 21st century dilemma. In 2003, we traveled to the Illinois River to learn about the Asian carp. These invasive fish were wreaking havoc on the water by jumping in front of boats and jet skiers. But the real damage was ecological.

Mike Conlin:
These fish are so numerous and reproducing in such large quantities, they're taking over the habitats. 

Andy Soth:
These imported fish had escaped from Arkansas fish farms and spread rapidly through the Mississippi and its tributaries. Something needed to be done before the Asian carp reached Lake Michigan and put the multibillion dollar fishing industry at great risk. In 2003 that something was an experimental electrical barrier that functioned like an electric fence to keep fish from crossing this point and reaching Lake Michigan. At that time, Great Lakes advocates were calling on Congress to pass legislation to create a permanent electric barrier.

Dennis Shorenak:
I want people to get mad as hell and get to Washington and tug on their congressman's sleeves and say, ‘We want that bill passed, the National Aquatic Invasive Species Act, because that's where the money, that's where the authority resides to solve this problem.’  

Andy Soth:
Congress did enact the legislation. But the problem is far from solved. One of two planned new barriers was built, but since 2006 it's been undergoing safety testing. The experimental barrier located southwest of Chicago uses one volt per inch of electrical charge. The new barrier has a capacity of up to four volts per inch. This week the coast guard agreed that the new barrier could be turned on permanently, but only at the one volt per inch level. Scientists worry that level is not strong enough. Small fish are actually less affected by electricity, so while one volt per inch works on a fish the size of a mature carp, it may not on their offspring. Phil Moy is co-chair of the barrier advisory board.

Phil Moy:
Say Asian carp begin to spawn downstream. There's a high potential for them to then be present near the barrier.

Andy Soth:
Four volts per inch has been shown in small-scale tests to deter even little fish, but that level has not been determined to be safe for boats or their crews.

Chuck Shea:
We need complete safety testing at higher voltages before we will be able to operate barrier 2a at those higher voltages.

Andy Soth:
Even if the barrier were to work continuously at full capacity, environmentalists and scientists say it's no permanent solution.

Andy Soth:
Some would like to see the canal closed.

Joel Brammeier:
If you really wanted to solve the problem, you had to get serious about hydrogeologically separating the Great Lakes and the Mississippi, cutting off that water supply.

Phil Moy:
If we're talking long-term effectiveness on a whole array of organisms, we're going to have to go with something a lot more permanent, a lot more physical probably than these behavioral barriers.

Andy Soth:
But closing the canal is not easy. It's the way wastewater is routed away from Chicago.

Joel Brammeier:
The water that people are using to brush their teeth and flush their toilets is forming the base of what's in the Chicago waterways.

Andy Soth:
Whatever permanent solution may be found will be a massive undertaking and clearly take a very long time. But that would not be unprecedented. After all, Chicago's waterways were constructed over a span of decades. For now, the electric barrier will have to do.  

Phil Moy:
The electrical array is a significant step in the prevention of aquatic species spread through the canal, but it's not going to stop everything. It's not an end-all. It's a good beginning.

Art Hackett:
Andy Soth reporting.