(Above) Asian carp in the custody of two U.S. Fish and Wildlife Service employees in Missouri on July 13, 2009. Photo by Steve Hillebrand. (Click on image to view larger version.)

January 16, 2015 – Tiny but suspicious signs of Asian carp have been detected again in the Chicago River.

The United States Fish and Wildlife Service says last October 20, they collected 57 samples from the river and found the DNA of silver carp, a variety of Asian carp, in five of the samples. Four months earlier, on June 2, 2014, silver carp DNA was found in two of 57 samples but on November 5, 2013, no DNA was found in all 19 samples.

They are also looking for bighead carp, another variety of Asian carp, but have not found its DNA in the Chicago River.

DNA cannot be collected directly from Asian carp, as only one has ever been spotted, so it is detected in the water. The “eDNA” can be found in water where a fish has been in the past few weeks but information is limited. It cannot tell how many fish there are, if they are alive or dead, or even if boats, birds, or other means transported the DNA.

The Fish and Wildlife Service is trying to keep the large, hungry, and prolific Asian carp away from the Great Lakes. The carp came up the Mississippi River and if it gets as far as Chicago, it can make it to Lake Michigan. And there are four other pathways.

The U.S. Army Corps of Engineers is trying to make sure that does not happen but they are dealing with a determined fish. An electric barrier was installed south of Chicago and in 2010, a 19-pound Asian carp made it past.