By JOHN FLESHER
AP Environmental Writer
TRAVERSE CITY, Mich. (AP) - The U.S. Army Corps of Engineers announced Monday that it is restoring a higher power setting on an electric barrier designed to prevent Asian carp and other fish from using a Chicago-area waterway to migrate between the Great Lakes and Mississippi River systems.
The corps announced in October that it was ramping up the juice in the barrier about 37 miles by water from Lake Michigan. But shortly afterward, power was reduced to its previous level because of concerns that it might be affecting signals on a nearby railroad.
Investigators identified a piece of equipment that was causing the problem and reconfigured it, the corps' Chicago district office said. The barrier was scheduled to be returned to the higher setting Tuesday.
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"The corps remains committed to operating the barriers safely and effectively," said Col. Frederic Drummond, the district commander. "We have high confidence in the effectiveness of the barriers and continue to work with our partners and stakeholders to assess the Asian carp threat and make informed decisions regarding barrier operations."
The barrier is one of three in the Chicago Sanitary and Ship Canal, part of a man-made waterway linking Lake Michigan to the Mississippi basin. The canal could provide a pathway to the Great Lakes for the large, voracious carp. Scientists say if allowed to gain a foothold in the lakes, the carp could destabilize the food chain and damage the $7 billion fishing industry.
The corps boosted the power level last month from 2 volts per square inch to 2.3 volts and also intensified the duration and frequency of pulses after research questioned whether the force field was strong enough to stop tiny fish.
In a statement Monday, officials said baby Asian carp had been observed in spawning areas more than 150 miles from Lake Michigan but were not believed to be near the electric barrier.
Scientists have detected Asian carp DNA beyond the barrier. But the corps says it has tagged numerous fish in the area and none have swum upstream through the electric field.
Drummond said even though he is confident the system is working, the higher settings will be used "as a conservative precaution."
Michigan, Minnesota, Wisconsin, Ohio and Pennsylvania are suing the corps in federal court, contending the only way to stop invasive species migrations between the Great Lakes and Mississippi basins is to physically separate them.
(Copyright 2011 by The Associated Press. All Rights Reserved.)