What discovery of Asian carp DNA in Lake Michigan means

[Spiel]

What discovery of Asian carp DNA in Lake Michigan means

 

 

January 21, 2010

By Jim Harger / The Grand Rapids Press

 

View infographic

 

 

Asian carp jump out of the water after being

disturbed by the sounds of passing boats

in the Illinois River in December. / AP File Photo

 

Call it "CSI: Lake Michigan."

 

Forensic testing of Chicago's shipping channels have spawned new fears Asian carp are invading the Great Lakes.

 

But scientists say the DNA evidence gleaned from the tests also may be the early warning they need to stop the voracious fish from staging a full-scale takeover in the Great Lakes.

 

View infographicThis week, federal officials announced a sample taken from Calumet Harbor in Lake Michigan last Friday contained "environmental DNA" they can trace to an Asian carp.

 

Other samples collected in the past eight months found Asian carp DNA throughout the network of manmade channels and re-routed streams that link the Illinois River and Lake Michigan.

 

They have not found the fish, but researchers say the presence of environmental DNA probably means they are in the water.

 

"The best human analogy is the DNA you might find in dandruff, on a hair follicle, in saliva, or in feces or urine," said Lindsay Chadderton, an aquatic ecologist from New Zealand.

 

He is on a four-man team conducting the tests from laboratories at the University of Notre Dame in South Bend, Ind.

 

"The DNA from fish could come attached to scales, or mucus or shed from gills or the mouth area," said Chadderton, who is employed by The Nature Conservancy, a non-profit environmental group that has partnered with Notre Dame's Center for Aquatic Conservation and the U.S. Army Corps of Engineers.

 

"The beauty of water is that those cells stay up in suspension," said Chadderton, whose team has collected more than 700 water samples in the manmade waterways and channels that link the Illinois River and Lake Michigan.

 

After collecting the samples, the team filters out the sediment and uses chemical markers to identify DNA that is specific to the Asian carp. It takes about two days to get the results, Chadderton said.

 

Without the DNA evidence, it would be much harder to know the invasive species had arrived, according to Duane Chapman, a research biologist and expert on Asian carp.

 

"These fish are remarkably cryptic," said Chapman, who is with the U.S. Geological Survey in Columbia, Mo. "They are very sensitive to nets and boats. They are not caught by accident by guys with rods and reels."

 

By the time Asian carp make themselves known, they tend to be breeding and well-established, he said.

 

"It's typical for a species to putter along at a barely noticeable level for several generations," Chapman said. "But when you get the density high enough, you are definitely going to start noticing them."

 

If Asian carp are established in the Great Lakes, experts fear they could devastate the region's $7 billion sports fishing industry.

 

Still, Chapman said it's not certain if Asian carp would take over the Great Lakes if they get in. The fish need long rivers to spawn, and some lakes may not offer enough plankton on which to feed, he said.

 

Currently, two Asian carp species -- the bighead and silver -- dominate the fish population in parts of the Mississippi, Missouri and Illinois river basins and are showing up in the Ohio River basin, Chapman said.

 

Silver and bighead carp feed voraciously on plant and animal plankton, robbing other fish species of food supply. They can grow to more than 100 pounds. Silver carp are known for leaping out of the water when they are disturbed by power boats or electric shocks.

 

They entered the Mississippi River in the 1970s or 1980s when they escaped from flooded fish farms in Arkansas. The farming operations imported the fish from China in the early 1970s to clean their ponds of algae.

 

Chadderton's team began testing for Asian carp in Chicago's waterways last summer after it was feared electric barriers built to keep them out of the Great Lakes had failed or were breached during flooding on the Calumet River. Researchers found their first DNA sample of Asian carp on Nov. 17.

 

Chicago's Calumet River system is the primary link between the carp-infested Mississippi River basin and the Great Lakes and St. Lawrence Seaway, which leads to the Atlantic Ocean.

 

The discovery of Asian carp DNA above the Calumet River's locks and electric barriers triggered several legal and political developments.

 

Michigan Attorney General Mike Cox asked the U.S. Supreme Court to reopen the 80-year-old Supreme Court case that allowed Illinois to create the waterways and channels. The High Court on Tuesday rejected Cox's attempt to close the waterways' locks on an emergency basis, but left open his request to reopen the case.

 

Michigan Gov. Jennifer Granholm and Wisconsin Gov. Jim Doyle, both Democrats, have lobbied President Barack Obama to host a summit on the Asian carp. They want to persuade his administration to take action in his hometown, despite local shipping and boating pressure to keep the locks open.

 

The White House Council on Environmental Quality announced Wednesday it wants to hold such a gathering early next month.

 

Meanwhile, U.S. Rep. Dave Camp, R-Midland, introduced legislation Wednesday to immediately halt potential entry of the carp into the Great Lakes.

 

The Close All Routes and Prevent Asian Carp Today (or CARP ACT) would direct the Army Corps to close the O'Brien Lock and Dam and Chicago Controlling Works until a controlled-lock strategy is reached. It also calls for additional barriers to be put up in nearby waterways to keep the carp from getting into Lake Michigan.

 

Despite the DNA tests, federal officials and scientists say it is too early to conclude the battle against the Asian carp has been lost.

 

"We feel confident that despite this new information, we can still win this fight," said Gen. John Peabody, of the U.S. Army Corps of Engineers, during Tuesday's announcement DNA had been found in Calumet Harbor.

 

He said they do not know how the DNA got into Lake Michigan, but added they are not ready to close the locks -- though with the Asian carp could swim toward Lake Michigan.

 

The DNA could have come from Asian carp that got past the barriers during a 2008 flood, it could have come from ballast water dumped by ships that were in the Illinois River or could be from individuals who caught Asian carp elsewhere and dumped the waste after cleaning the fish, he said.

 

"We are taking it as an early warning that it may be live carp," Peabody said.

 

He said the Army Corps will conduct more tests with netting and electric shocking to see if they can find any Asian carp, dead or alive.

 

Meanwhile, the Notre Dame-based team will triple its capacity to analyze water samples and conduct sampling beyond the Chicago water system into Lake Michigan, Peabody said.

 

-- The Associated Press contributed to this story.