Scientists Address Efforts To Downplay Asian Carp Threat To Great Lakes

Scientists Address Efforts To Downplay Asian Carp Threat To Great Lakes

An independent, peer-reviewed scientific paper refutes four main misconceptions opponents use against progress on halting the Asian carp’s migration from the Mississippi River into the Great Lakes. The report addresses five main claims; below is just one of these. The remaining ones can be found on our website, www.freshwaterfuture. org/asiancarp.

Claim: An electric barrier operating in Chicago waterways is effective in blocking Asian carp; the Asian carp captured above the barrier arrived by human transport or other means.

Scientists’ response: “After more than a year of environmental DNA testing, electrofishing, netting and rotenone (fish poison) applications, no consensus has emerged among federal and state agencies responsible for control measures as to whether or not the existing electrical barriers have been effective in blocking Asian carp under a variety of river conditions,” the scientists write.

The authors state that electric barriers have numerous shortcomings, among them that they’re limited in the sizes of fish they can block and must be shut down for periodic maintenance. Such “barriers” are also subject to unexpected shutdowns from flooding, power interruptions, debris and human safety concerns.

The scientists note that the greatest deficiency of electrical barriers and other such permeable devices is their inability to block both upstream and downstream movement of all kinds of invasive aquatics, including fish, plants, disease organisms and parasites. “An electric field strength low enough to ensure safety of people falling into the water from barges and other watercraft will do little to prevent downstream migration and drifting of invertebrates, fish eggs and larvae, and other potentially harmful plants, parasites and disease organisms,” they write.

Widely publicized press reports following the June 2010 discovery of a live Asian carp beyond the barrier “confused the public by erroneously reporting various speculations and misinterpretations of research results” write the scientists. Analysis of the fish by Southern Illinois University researchers “concluded absolutely nothing about what path the carp might have taken to get to the Chicago area canal system from the lower Illinois River. But a State of Illinois press release asserted that the carp in Lake Calumet could have been the result of a human introduction, without even mentioning the possibility that the electrical barrier may have failed or been bypassed.”



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Images courtesy of Steven Huyser-Honig,
West Grand Boulevard Collaborative, & Yellow Dog Watershed Preserve.