DNR: Miss. River tests find only slight evidence of invasive carp

Asian carp seemed to be on the march when fishermen near Winona caught two critters in the Mississippi River in 2012 and another was found north of Winona in 2013.

So it's cause for at least some relief that water samples collected in August from Mississippi River pools in southeast Minnesota indicate only a small presence of bighead carp DNA.

Only 1 of 500 samples tested positive for invasive carp, the Minnesota Department of Natural Resources said Monday. One result came back positive for bighead carp, while none of the samples tested positive for silver carp, the DNR said. Results were analyzed in December.

"The lone positive bighead result appears to support historical, physical catch evidence of low numbers of invasive carp in this stretch of the Mississippi River," Nick Frohnauer, DNR invasive fish coordinator, said in a statement. "Individual captures of adult bighead and silver carp have occurred since 2008 but none were captured in these pools in 2014."

The U.S. Fish and Wildlife Service and DNR used a new technology called environmental DNA sampling to analyze the data. "The presence of eDNA does not provide physical proof of the presence of live or dead carp, but indicates the presence of genetic material in the water body," the DNR said.

Officials said the testing and test results can't yet be used to estimate an invasive carp population. But they plan to collect samples at the same pools and possibly move testing farther north each year.