The samples were taken by the U.S. Fish and Wildlife Service, which is monitoring Great Lakes tributaries for signs of the invasive fish.
DNA from bighead and silver carp has been detected in Chicago-area waterways, raising concerns that they may be near Lake Michigan. Both were imported from Asia. Officials are trying to prevent them from reaching the Great Lakes, where they could out-compete native fish for food.
As part of a larger monitoring program, tributaries of Lake Michigan also were sampled, the Michigan Department of Natural Resources said. They are the Muskegon, St. Joseph and Grand rivers.
Tests were also conducted on Lake St. Clair, the Detroit River and tributaries of western Lake Erie. Test results for these locations will be available later this year, the DNR said.
The state agency said it is asking boaters and anglers to report fish they think may be Asian carp.