Last week’s fish poisoning located no Asian carp in the Calumet River – “good news for Illinois business leaders and politicians who have been highly critical of a push by Great Lakes regional politicians to close two navigation locks to block the advance of Asian carp into Lake Michigan,” the Milwaukee Journal-Sentinel reports (via Progress Illinois).
The results didn’t surprise wildlife scientists – who warn that they don’t prove the absence of carp.
A small number of Asian carp could be very hard to locate, US Geological Survey expert Duane Chapman has said. “It’s typical for a species to putter along at a barely noticeable level for several generations,” he told the Grand Rapids News in January. They may not be noticeable until they are a well-established population, he said.
In addition, the DNA traces which the fish kill focused on are at least a month old, Thom Cmar pointed out at NRDC’s Switchboard. “Just because there were Asian carp there a month ago does not mean they sat still and did nothing in the meantime.”
As the scientists who pioneered the DNA testing told the Chicago Reader in March, alternative hypotheses to account for the traces – involving birds or wastewater carrying carp DNA – don’t explain the pattern of the evidence, especially the repeated findings of DNA traces at the same locations.
“These results are not chance events, and the distribution is consistent with the movement of fish,” said Lindsay Chadderton. “For example, the number of positive samples decreases as we get closer to the barrier. That’s consistent with an upstream invasion.”
What NRDC’s Henry Henderson calls “the ‘show me a fish’ crowd” is trying to deny that the threat of an Asian carp invasion is serious – and sidestepping the larger question, the ongoing threat to the integrity of the Great Lakes from invasive species caused by Lake Michigan’s artificial linkage with the Mississippi River.
Henderson fears that netting and poisoning operations which aim at producing “physical evidence” to confirm “indications” from DNA (as a federal official told the Milwaukee Journal-Sentinel) are sucking up resources that should go to a long-term solution.
“The Asian Carp Control Strategy framework is overwhelmingly tipped towards short-term tactics, with only $1 million of their stated $78.5 million budget devoted to the study that is intended to determine the permanent solution,” Henderson pointed out.
“In 2007 Congress authorized the corps to look at ways to stop the spread of invasive species between the two waters,” according to the Alliance for the Great Lakes. “The corps’ study, however, focuses on a variety of approaches to controlling invasive species—none of which is 100 percent effective—and does not look at the only permanent solution to the problem: building a physical barrier between the two waters.”
So it’s significant that U.S. Senators from the Great Lakes, reaching across the divide that’s separated Illinois from neighboring states, issued a letter yesterday urging Congress to direct the U.S. Army Corps to study how to build a permanent barrier between the Great Lakes and the Mississippi.
Signing were Schumer and Gillibrand of New York, Specter and Casey of Pennsylvania, Voinovich and Brown of Ohio, Levin and Stabenow of Michigan, Kohl of Wisconsin, Klobucher and Franken of Minnesota – and Durbin and Burris of Illinois.
The senators joined the Great Lakes Commission (chaired by Governor Quinn), which in February called on Congress and the U.S. Army Corps of Engineers “to embrace a clear goal of ecological separation of the Great Lakes and Mississippi River watersheds as the key, permanent strategy in the war against Asian carp and their threatened invasion of the Great Lakes.”
Conservation groups praised the senators. “We applaud Senator Durbin for his leadership in seeking a long-term solution to the threat posed by Asian carp, and other invasive species, to Lake Michigan and our Illinois River system,” said Jack Darin of the Sierra Club in a release from the Great Lakes Coalition.
“For right now, we have little choice but to try to find and kill Asian carp,” Darin said, “but the study [the senators] are calling for gives us hope for a permanent fix that won’t require repeated poisonings of the Chicago River system.”