Ballast Water

Michigan Department of Environment, Great Lakes and Energy

The invasive aquatic plant called European frogbit was found in Oceana and Ottawa counties this summer. 

Frogbit is a small green plant that looks like a water lily. Kevin Walters with the Michigan Department of Environment, Great Lakes and Energy said it can form dense mats on the water's surface.

"So there’s no light penetration in the water, it makes movement of waterfowl and fish difficult," Walters said. "For humans it makes access to the water for fishing, swimming, boating, things like that can become very difficult."

This week, the 2nd Circuit U.S. Court of Appeals in New York ordered the Environmental Protection Agency to write new rules for the ballast water in ships.

Four environmental groups sued the EPA over its current ballast water rule.

Invasive species can get into the Great Lakes in ballast water. Salties are ships that cross the ocean, and lakers are ships that travel only within the Great Lakes. In the decision, the judges criticize the EPA for exempting lakers from certain regulations. 

There are more than 180 species in the Great Lakes that are not supposed to be here.

Euan Reavie is a researcher with the University of Minnesota-Duluth.

“Duluth-Superior harbor is the most invaded freshwater port in the world,” Reavie says. “This is kind of the end of the water road for a lot of ships that come in here.”