Great Lakes
In this file photo taken May 10, 2011, jumping Asian carp feed off the muck filled floodwater off President's Island in Memphis, Tenn.

Asian Carp 'eDNA' found in Chicago creek near Lake Michigan. But what does it mean?

The Great Lakes are in imminent danger of being overrun with invasive Asian carp, now appearing on the doorstep of Lake Michigan. Or, something else is going on.

For the first time, researchers have found DNA from two types of invasive Asian carp in Bubbly Creek off the Chicago River's South Fork, only about 2½ miles from Lake Michigan.

That's alarmingly close. Should invasive Asian carp make it into the Great Lakes, many scientists believe they would cause a huge disruption to the aquatic food chain and damage, perhaps irreparably, a $7 billion annual Great Lakes fishery.

But there's a catch: The findings are so-called environmental DNA, or eDNA. The samples don't come from the fish themselves, but via an emerging science that allows researchers to find the DNA of individual species — in this case bighead and silver carp — in water samples, using sophisticated collection and testing methods.

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