A new plan of attack against the spread of Asian carp into Lake Michigan calls for a second round of chemical poisoning, this one in the Calumet-Sag Channel.
That will cause closure of the waterway to boat and barge traffic for at least five days beginning May 20, officials with the Asian Carp Regional Coordinating Committee announced Wednesday.
The Cal-Sag Channel is a direct shipping route linking Lake Michigan with the Chicago Sanitary and Ship Canal and, eventually, the Mississippi River. Fish biologists will use the chemical, rotenone, over a narrow 2-mile stretch of the channel downstream from the lock and dam.
Rotenone was the chemical the Illinois Department of Natural Resources used in December to kill thousands of fish from the Chicago Sanitary and Ship Canal while engineers disabled the underwater electric barriers for maintenance. Officials say rotenone is not believed to be dangerous to humans or wildlife.
The chemical will be dispersed on May 20, officials said, with fish recovery lasting four to five days.
This is a section of the channel where DNA evidence has indicated the presence of Asian carp. But since officials have yet to positively identify a bighead or silver carp in those waters after months of intense searching, some now are questioning the validity of the DNA research.
Officials said the rotenone application will be used to determine how many, if any at all, Asian carp exist in that stretch of water south of the dam.
In addition to the closure of the Cal-Sag Channel later this month, the new Asian carp response plan released Wednesday calls for a portion of the North Shore Channel to be closed to kayakers and recreational boaters for three days next week while researchers use nets and electric shock to search for Asian carp in that portion of the river system.
The closures will begin Tuesday; the river will reopen May 14.
"The trade-off is worth it because our hope is the poisoning will prove once again there are no Asian carp above the electric barriers," said Jim Farrell of the Illinois Chamber of Commerce, one of the staunchest critics of proposals that would close Chicago-area locks.
"I don't know any business that would want to be out of business for a week by mandate. But in the long run this might help our situation when, as we believe, they don't find any carp," said Farrell.
Several million tons of materials, from road salt to petroleum, travel along the Calumet-Sag Channel on barges and cargo ships. While closing that portion of the shipping corridor won't devastate business as a permanent lock closure would, Farrell said, even a weeklong shutdown would put the squeeze on businesses during a typically busy time of year.
But he also knows the financial impact will be short-lived.
"As long as this is a unique event and not a monthly endeavor, we'll be fine," Farrell said of shipping business in Chicago. "As inconvenient as it might be, it's further proving the point that Asian carp are not an immediate threat to Lake Michigan."
Others, though, said the urgency to perform another rotenone application signals the need to large-scale solution.
"This will mark the second time we are intentionally poisoning our waterways in reaction to the carp invasion," said Henry Henderson of the Natural Resources Defense Council.
"Doing this within a mile of the Lake is a remarkably clear signal that this threat is imminent. We need to get rolling on the permanent solution so we can stop killing sports fish and start physically separating these ecosystems. If the electric barrier was working, there would simply be no reason to undertake these operations," Henderson said.
Explore further: Population genomics unveil seahorse domain