Invasive Asian carp, which have been the scourge of ecosystems as they've made their way northward in several U.S. rivers, have been found 12 miles closer to Lake Michigan than ever before, experts say.
The carp, voracious eaters that can damage habitats and out-compete native fish for food sources, could threaten a fishing industry worth around $7 billion if they reach the Great Lakes, federal scientists say.
A nonnative fish, Asian carp—an umbrella term for four species, Bighead, Silver, Black and Grass carp—were introduced to the U.S. in the 1970s to help keep algae down in the catfish ponds of Arkansas fish farms.
They escaped to become a scourge in much of the watershed regions of the Mississippi River and beyond, breeding quickly and dominating ecosystems, feeding on food supplies vital for larval native fish and mussels.
Adult Asian carp can grow to 7 feet long and weigh more than 100 pounds.
As the fish moved northward, there was increasing concern about the damage they could cause if they moved into the Great Lakes.
The newest discovery, in the Illinois River upstream of Seneca, Ill., "brings the leading edge of juvenile Asian carp detections about 66 miles closer to Lake Michigan than it was at the beginning of 2015," the Asian Carp Regional Coordinating Committee said on its website.
Politicians in affected states have called for immediate action to stop the spread of Asian carp.
"I remain extremely concerned that Asian carp are getting closer," said Michigan Democratic Sen. Debbie Stabenow. "Time is running out."
Officials say that despite the new discovery, there are still 76 miles of waterways, three dams and electric dispersal barriers between Asian carp and Lake Michigan.
Still, Stabenow and other politicians are urging the Obama administration to provide funds for research into ways to block the advance of the carp at key points in waterways leading the lake.
The administration has so far set aside $200 million to study the invasive species and research how they might be contained.
A Great Lakes and Mississippi Interbasin study conducted by the U.S. Army Corps of Engineers in 2014 has presented several options for dealing with the fish, all of which carry hefty price tags and could take years to implement.
"I will continue to urge the Army Corps of Engineers and the U.S. Fish and Wildlife Service to take immediate action to protect the Great Lakes basin from this terrible threat," Stabenow said.