0319 GMT May 22, 2019
A crew from the University of Toledo working with the US Geological Survey found the larvae during sampling last June in the Maumee River, a Lake Erie tributary, AP wrote.
Grass carp, which have been found on the Maumee and Sandusky rivers, destructively feed on aquatic plants.
Nicole King is a University of Toledo research associate. She said the hunt for signs of spawning in other Lake Erie tributaries means more work and expense.
The Blade reported King said the fish would be easier to control if they were in just one river.