AP Environmental Writer
TRAVERSE CITY, Mich. (AP) - Genetic material from an invasive fish called
the Eurasian ruffe has been found in southern Lake Michigan for the first
time, raising the possibility that it could migrate into the Mississippi
River watershed and compete with native fish there, a scientist said
Researchers testing Great Lakes waters for signs of Asian carp and other
invasive species detected DNA from the ruffe in two samples taken in July
from Lake Michigan’s Calumet Harbor at Chicago, said Lindsay Chadderton of
The Nature Conservancy, a member of the team.
No actual ruffe were seen. State and federal officials downplayed the
likelihood that the DNA discovery signaled a significant presence of the
exotic fish even as they urged anglers to be on the lookout for them. Still,
Chadderton urged the agencies to take the threat seriously and step up
monitoring of Chicago-area waters.
“This could be the first indication that Eurasian ruffe are on the cusp of
using the Chicago canal system to invade the Mississippi,” he said.
An engineered network of rivers and canals in and around Chicago is the
flashpoint in a regional debate over invasive species. Five states have
urged federal courts to order measures that would sever links between the
Great Lakes and Mississippi systems, preventing fish and other organisms
from moving between them.
The U.S. Army Corps of Engineers, under orders from Congress, has pledged to
produce a list of options by early next year, including placement of
barriers in the waterways.
The Eurasian ruffe is among 29 species the Corps has identified as leading
candidates to migrate between the two systems. A small fish that resembles
and is related to the yellow perch, it is believed to have hitched a ride in
a freighter’s ballast tanks from Europe to Lake Superior’s Duluth Harbor in
It has spread across Lake Superior and to limited sections of northern Lake
Michigan and Lake Huron, where it competes for food with perch and walleye,
two prized sport and commercial species. Even so, the U.S. Fish and Wildlife
Service says native species don’t appear to have been significantly harmed.
The Nature Conservancy, the University of Notre Dame and Central Michigan
University have been sampling Great Lakes tributaries and bays since 2009
for genetic fingerprints of invasive fish. They’ve found Asian carp DNA in
the Chicago waters and in Lake Erie.
Fish leave their DNA in slime and body wastes. Army Corps scientists say it
also can be transported by birds, boat hulls and fishing nets.
Kevin Irons, aquatic nuisance species program manager for the Illinois
Department of Natural Resources, said it’s not surprising that Eurasian
ruffe DNA would turn up in Calumet Harbor, with its heavy commercial
shipping traffic. State agencies monitor the harbor with electrofishing and
nearshore waters of Lake Michigan with nets.
“To date, we have not captured any ruffe, and in fact we don’t believe
Eurasian ruffe are established anywhere in southern Lake Michigan,” Irons