TRAVERSE CITY, Mich. -promised federal officials Friday to improve two crucial weapons in the fight to prevent Asian Carp from invading the Great Lakes: a barrier of electric fish near Chicago and a warning system that detects DNA carp in waterways.
The U.S. Army Corps of Engineers issued a report by four independent scientists who analysed the process of "Environmental DNA" that the Government and University scientists have used these past two years for carp on both sides of the fence.
The study has found the means of detection of the water samples carp genetic material are fundamentally sound, but should be refined to respond to questions such as whether the DNA came from live carp and, if so, how. Research to improve the system is underway, said responsible of Corps.
The body also announced it was turning up the juice on the network of barrier in the Chicago Sanitary and ship Canal, an artificial link between Lake Michigan and the Mississippi River system. The barrier is designed to prevent the Asian and other carp fish migration between watersheds and competition with native species for food and living space.
The administration of the Obama is committed to more than 125 million dollars to protect Great Lakes Bighead and silver carp, Asian varieties from southern farms and lagoons of wastewater in the 1970s, who have migrated to the North in the Mississippi River and tributary rivers. Scientists say that if the aggressive carp settled in the Great Lakes, they may starve other fish being small fish and plants at the base of the food chain.
Five States--Michigan, Ohio, Wisconsin, Minnesota and Pennsylvania - filed a federal suit called for a re-engineering of the Chicago canal to break the links between the drainages of the Mississippi River and Great Lakes. The plans of Corps to release a report and possible alternatives to long-distance migration of the species in 2015. Chicago business interests say cut the link between watersheds would devastate the shipping companies that use the canal.
A key issue in the debate is well provides the barrier electric 37 kilometres south of Chicago.
The body of the army, said there is no evidence that any carp have managed to pass. The five States and environmentalists argue that it is not infallible, pointing to the discovery of Asian Carp DNA, also known as "eDNA", in dozens of samples of water the barrier since the fall of 2009. Business groups have questioned the reliability of the conclusions of the DNA.
In the report released Friday, the independent scientists said the methodology used to detect DNA carp in water has been solid. But they called for improvements, saying that it "does step unequivocally indicates the physical presence of live carp and silver carp.".
David Lodge, the biologist from the University of Notre Dame which the team developed the DNA process, said that he never claimed otherwise. The advantage of DNA is that it is easier to find than live fish, so it provides an early indicator that carp may be present, he said.
"This should bring to closure of issues, on the technical robustness or the utility of eDNA" said Lodge. "This should also make it possible to move quickly to provide more refining tool types of information that pointed out the independent review team would be useful."
While insisting the barrier is stopping migration of fish, the body said Friday that tests showed the tension could be increased about 15 percent - of 2 volts per inch to 2.3 volts per inch - not endanger persons in the passage of vessels.
The adjustment will take place this fall and make even more effective, the barrier, said major-General John Peabody, commanding officer of the Division of the Ohio River and Great Lakes. In addition, the frequency of the barrier is doubled and its electrical impulses will become faster.
"We believe that it is prudent to take all possible precautionary measures as long as we can do them safely," Peabody said in a conference call with journalists.
The Army Corps said that his confidence in the barrier is based on movements of 166 fish equipped with tags of the transmitter. Although the tracking devices tags recorded 1.9 million visits, no fish were seen passing through the barrier, said Peabody. A tag was found on the other side, but it seems that the fish was hooked by a fisherman, said Kelly Baerwald, a biologist and fishing of the body.
In June, the Corps released six fish - Asian Carp step - just above the barrier. Two passed through the force field but have apparently been restrained, while two others entered the field and apparently killed. The last two swam upstream, said Peabody.
"We believe that the barrier is effectively prevented the movement of these marked fish", he said.
Thom Cmar, an attorney with the Natural Resources Defense Council, said the barrier seems to work most of the time, but is not infallible.
"When you have thousands of Asian Carp teeming in the rivers of Illinois and closer barriers all the time, there is every reason to believe that some of them are testing the barriers today,"said CMAR."
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