Officials say poisoning mission in Chicago-area river kills many fish, but no Asian carp found

Chicago poisoning operation finds no Asian carp

TRAVERSE CITY, Mich. — A poisoning operation aimed at rooting out the voracious Asian carp in a Chicago-area river before they make their way into the Great Lakes didn’t turn up any of the unwanted fish, Illinois officials said Monday.

Officials said more than 100,000 pounds of dead fish had been collected since the poisoning five days ago. They say the operation suggests few if any Asian carp are near a shipping lock that Michigan and neighboring states want closed for fear it could provide an opening to Lake Michigan. Scientists had detected genetic material from the carp in the area.

Federal agencies and the Illinois Department of Natural Resources spread Rotenone, a chemical toxic to fish, along a 2.5-mile section of the Little Calumet River on Chicago’s South Side on Thursday.

They also temporarily closed the T.J. O’Brien Lock and Dam, despite objections from shippers whose vessels regularly use the structure. It will reopen in a day or two, DNR spokesman Chris McCloud said.

Fish representing more than 40 species were found after the poisoning, but no bighead or silver carp — Asian varieties that have been migrating up the Mississippi and Illinois rivers toward the Great Lakes for decades. Scientists say if they establish breeding populations in the lakes, they could disrupt the food chain and devastate the $7 billion fishing industry.

“We now know that if Asian carp exist near the … O’Brien Lock, they exist in very low numbers,” said John Rogner, assistant director of the Illinois DNR.

The poisoning was ordered because the river segment is among places where biologists have found Asian carp DNA beyond an electronic barrier about 20 miles downstream from Chicago.

No actual bighead or silver cap, alive or dead, have turned up past the barrier despite extensive searches. But officials in Michigan and other Great Lakes states used the DNA results as evidence when unsuccessfully petitioning the U.S. Supreme Court to close the Chicago shipping locks.

Illinois business interests have questioned the reliability of the DNA screening methods, developed by biologists with the University of Notre Dame and The Nature Conservancy.

Jim Farrell, executive director of the Illinois Chamber of Commerce’s Infrastructure Council, said the fish kill results show that Asian carp have not breached the barrier.

“I’m glad we got the proof we needed to move the battle 40 miles downstream from Lake Michigan” to waters known to be infested with carp, he said.

McCloud said government agencies still believe the DNA tests reveal the presence of Asian carp genetic material but don’t explain how it got there or how many fish might be in the area.

The next step is to analyze results of the poisoning mission “to see if we can draw any further conclusions about the risk of carp invading and becoming established in Lake Michigan through the Chicago waterway system,” he said.

Joel Brammeier, president of the Alliance for the Great Lakes, said DNA screening remains the most reliable means of detecting Asian carp.

“The overwhelmingly likely explanation for this material being in the water is that it’s coming off fish,” he said.

Also Monday, more than a dozen U.S. senators from Great Lakes states called for a study of building a physical barrier between the lakes and the Mississippi River watershed that would prevent species from migrating from one system to the other.

In a letter to the Environment and Public Works Committee, the senators asked Congress to order the U.S. Army Corps of Engineers to conduct the analysis.