Scientists have identified the non-native species Mesocyclops pehpeiensis in Lake Erie. (Courtesy of Cornell University/Elizabeth Whitmore and Joseph Connolly)
The U.S. Environmental Protection Agency says Cornell University researchers confirmed the species are in Lake Erie.
The species are Diaphanosoma fluviatile, which is from Central and South America and the Caribbean, and Mesocyclops pehpeiensis, which is native to tropical and temperate areas of Asia.
Scientists don't know how the zooplankton entered the lake but say this is the farthest north either species has been tracked in the Western Hemisphere.
Experts say the discovery is the planet's largest freshwater system is alarming. Researchers are uncertain what risks the tiny creatures may pose. The university plans to monitor the situation but says both species haven't been deemed invasive because of their low abundance.
The findings are part of the EPA's biology monitoring program in the Great Lakes.