The latest round of testing for evidence of Asian carp DNA revealed one positive water sample for silver carp out of 325 samples drawn from the Maumee and Sandusky rivers, the Ohio Department of Natural Resources said.
No live fish were found.
The Ohio DNR said it plans to do more testing with the U.S. Fish and Wildlife Service.
The presence of Asian carp DNA does not necessarily mean those fish are present, said officials, who have said other potential pathways exist.
The one positive result was from 225 samples drawn from the Maumee. None were found in 100 drawn from the Sandusky.