Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=154284
Story Retrieval Date: 5/20/2013 1:52:50 PM CST
Courtesy of Frank Avila
Officials gathered at a public hearing hosted by State Senator Susan Garrett, D-Lake Forest, to gather solutions and suggestions for the growing carp crisis.
The invasive fish with a voracious appetite has journeyed up the Mississippi River from Louisiana right to Lake Michigan’s front door.
Officials agreed at the hearing to continue short-term prevention measures, such as rotenone poisoning, netting and the construction of more electric barriers. But long-term measures have not been determined, the said at the hearing held at the James R. Thompson Center, state headquarters in Chicago.
“We need more time,” said Colonel Vincent Quarles of the U.S. Army Corps of Engineers. “We need to know what solutions are available and what impact they will have before we can be sure.”
Quarles said studies usually take three to five years, but measures are being taken to expedite permanent solutions for the Chicago area.
Other officials pointed to problems with quick fixes, such as closing the locks, which would cause flooding in Chicago during heavy rains.
The U.S. Supreme Court’s decision Tuesday to deny Michigan’s request for the immediate closure of Chicago locks leaves Illinois in charge of protecting the lake’s ecology and economy for now. Meanwhile, the White House annnouned plans to gather Great Lakes region governors to a February summit on the carp problem.
Quarles said electric barriers will continue to be built to deter the fish from reaching the lake. However, the exact locations for additional barriers and the long-term effectiveness of them are not known.
“The barrier is not a silver bullet, but separating the waterways can help,” Quarles said. “We are also identifying other locations to build these barriers.”
Current electric barriers are located above the Lockport Lock and Dam.
Duane Chapman, a research fish biologist with the U.S. Geological Survey, is a leading expert on Asian carp.
Chapman clarified at the hearing that Asian carp can survive in Lake Michigan and live healthy lives, but it’s unlikely they can reproduce there. The fish depend on rivers to spawn, and Chapman said researchers do not know if the fish would be able to sustain a population in the lake.
“Individual fish would do quite well in the lake, but we do not have an understanding of whether the young fish would be able to survive,” he said.
Nevertheless, officials agreed that assumptions should not be taken as fact. Although more research is needed to understand the real impact of the carp on the Great Lakes, it is wise to continue devising preventative actions against the elusive fish, officials said.
“It will take decades for any signs of the Asian carp invasion to show,” said Chapman. “Five to 10 years from now we won’t be able to find them in the lakes and we’ll think we overreacted to the threat. Then 20 years after that the shoe will drop.”
The Army Corps announced earlier this week that eDNA tests detected the possible presence of carp in Calumet Harbor, which is in Lake Michigan, and the Calumet River.
The eDNA, or environmental DNA, comes from the sampling of scales or wastes that could have been carried in from other locations. However, results mark the fifth detection of carp DNA beyond the electric barriers meant to keep the fish out.
Although officials take eDNA results seriously, they acknowledge that the test cannot confirm an actual presence of live carp. DNA can easily be washed into the canals and harbors through sewage or baiting.
“This information is important for appropriate management decisions to be made,” said Maj. Gen. John Peabody of the Army Corps.
The eDNA test was developed at University of Notre Dame by Professor David Lodge. The Army Corps have been using it to pinpoint areas of highest concern.
“Because eDNA is an emerging technology, we have relative confidence in the testing but not total confidence,” Peabody said. “It is important to continue to work with the University of Notre Dame to do additional research.”
Scientists at Notre Dame are working to include more genetic information through eDNA testing as early as June, Peabody said. The sex, size and number of fish could all be extracted from water samples with improved testing.
However, Lindsay Chadderton, the aquatic invasive species director of the Nature Conservancy, stressed that eDNA testing remains a method of detection and not prevention. The interpretation of DNA results can also be misleading.
“If DNA is detected it doesn’t mean there are fish in that area, and, if DNA is not detected, it doesn’t mean fish are not present,” he said.