Posted Tuesday, June 19, 2012 --- 6:30 a.m.

DETROIT (AP) -- The U.S. Army Corps of Engineers says it has again found genetic material from invasive Asian carp in samples taken from waters near Lake Michigan.

The silver carp DNA findings from May 22 collections in Lake Calumet in Chicago and the Little Calumet River were posted online earlier this month.

Jared Teutsch, water policy advocate for the Alliance for the Great Lakes, said in a statement Monday the findings mean "another year of worry" about Asian carp.

Bighead and silver carp were imported from Asia. They have migrated up the Mississippi River and its tributaries. An electric barrier is meant to block them.

Dozens of water samples taken beyond the barrier in recent years have contained Asian carp DNA, although just one actual carp has been found there.