WASHINGTON – It appears that the Asian carp, the high-flying, habitat-destroying invader that has infested the rivers of the Midwest, may be closer than ever to infiltrating the Great Lakes.
Releasing data that it compiled last October, the U.S. Fish and Wildlife Service said it had found bighead or silver carp DNA throughout the Chicago area waterway system, long seen as the most likely gateway for the invasive fish to enter the Great Lakes. Perhaps most significantly, the study found Asian carp DNA near a lock in the Chicago River that’s less than one city block from Lake Michigan.
Presence of the DNA does not necessarily mean that live Asian carp are now on Lake Michigan’s doorstep, but the latest findings lead environmentalists to say that the Asian carp threat now looks more imminent than ever before.
“We certainly are concerned about it,” Todd Ambs, director of the Healing Our Waters – Great Lakes Coalition, said of the new data out of Chicago. “It’s continuing evidence that the Asian carp are certainly very close to Lake Michigan, and it just heightens the urgency of finding a long-term solution.”
The Fish and Wildlife Service collected 228 water samples in the Chicago area last October, and found Asian carp DNA in 23 of them. Perhaps most notably, the tests found eight samples of silver carp DNA in the Chicago River, which flows into Lake Michigan, including one such sample near a lock just short of the lake.
That’s a concern because silver carp – which are known for leaping out of the water and surprising, or even hitting, boaters – consume massive quantities of the kind of plankton that serves as the basis of the food chain that supports the Great Lakes’ $7 billion commercial fishing industry.
While it would take years for the fish to establish a breeding population in the lakes, scientists fear that they would be most likely to eventually do so in Lake Erie, whose comparatively warm and shallow waters would offer a plentiful food supply for the invaders.
“Asian carp in the Great Lakes would disrupt the food chain and disturb the natural ecosystem permanently,” said Sen. Kirsten E. Gillibrand, a New York Democrat who’s long supported more aggressive measures for stopping the spread of Asian carp in the Chicago area.
The latest findings prompted nine environmental groups to release a joint statement calling for more aggressive action aimed at preventing the fish from invading the lakes.
“DNA evidence is an early-detection tool to understand the potential movement of carp, and testing results have consistently found DNA hits on a path closer and closer to the Great Lakes over the past several years of testing,” the statement said. “We cannot afford to wait until a breeding population shows up in the Chicago River. Prevention needs to happen now, and the U.S. Army Corps of Engineers and other key decision makers should take swift action.”
The groups reiterated their call for a controversial but permanent solution: a hydrologic separation of the Mississippi River and the Great Lakes Basin. But in the meantime, they suggested several interim steps, including:
• Design of a new channel near a key lock in the Chicago River, which could divert invasive species from entering the lakes.
• Increased water controls at that lock.
• Research to see if reconfiguring other locks in the river would help prevent Asian carp from moving into the lake.
The Alliance for the Great Lakes spearheaded the joint statement, and the group’s president, Joel Brammeier, said the sheer number of positive DNA samples – which was higher than in past rounds of testing – served as a call to action.
“We still have an opportunity to extinguish this spark before waiting for the house to burn down,” he said.
Asian carp DNA also has been found more sporadically in other locations through the Great Lakes basin, including in Toledo, Ohio, and Green Bay, Wis.
But Brammeier said those isolated findings don’t pose the same level of concern as the consistent DNA findings in Chicago, which indicate the fish may be moving closer and closer to Lake Michigan.
After all, research five years ago showed Asian carp DNA several miles downstream from the lake, while the latest data shows it on the lake’s very threshold.
Still, the data does not make completely clear how immediate the Asian carp threat is.
While DNA evidence continues to be found beyond a set of electronic barriers put in place in Chicago to prevent the fish from entering Lake Michigan, only one live Asian carp has been found in Chicago-area waterways, and that happened nearly five years ago.
That being the case, the most recent DNA evidence is probably not from a live Asian carp, said Kelly Baerwaldt, Asian carp and environmental DNA program coordinator at the U.S. Fish and Wildlife Service’s Midwest office.
Asian carp DNA also can come from dead fish or from birds that have been in contact with them, or even from fishing nets that were not properly cleaned beforehand, she noted.
Still, positive DNA strikes show that there may be a concern in a particular area, which will allow authorities to focus on that area to make sure that the carp don’t spread beyond it, she said.
Kevin Irons, aquatic nuisance species program manager for the state of Illinois, agreed.
“Environmental DNA is an early-warning system,” said Irons, who added:
“I’m very confident that there are not a lot of fish, or a consistent level of fish, in the area,” he added.
Nevertheless, the early-warning sign was enough to alarm Jill Jedlicka, executive director of Buffalo Niagara Riverkeeper, who said that a hydrologic separation of the Mississippi River basin and the Great Lakes was the only way to fully protect the lakes from Asian carp.
“Lake Erie is the most vulnerable of the Great Lakes, and our region’s economy and ecology would be severely and permanently impacted should an Asian carp population become established,” she said.
Asian carp seen creeping closer to Great Lakes
Since 2013, Asian carp DNA has been found:• In the Chicago River, at a lock less than one city block from Lake Michigan.
• In the Maumee River in Toledo, Ohio, near the Martin Luther King Bridge.
• In the Muskingum River in southeast Ohio, north of the intersection with the Ohio River.
• In the Fox River in Green Bay, Wis.
• In the Kalamazoo River in Allagen, Mich.