TRAVERSE CITY, Mich. -

A 3 year study has revealed which of Michigan’s Great Lakes are most environmentally threatened.

On Monday, scientists revealed that Lake Erie and Lake Ontario are the worst off based on their analysis.

Researchers used scientific reports, satellite maps, and a survey of experts in order to find the most accurate information.

The lead researcher, David Allan, said the study will help the state set priorities as they plan a restoration program for the lakes.

"The death by a thousand cuts analogy is a good one because you have so many environmental stressors.  We looked at invasive species. We looked at coastal development. We looked at climate change. We looked at runoff from the land. We looked at fishing pressures, " Allan said.

Lake Erie has particular risks.

"It has more vulnerability to warming, more vulnerability to depletion, the loss of oxygen in its deeper waters," Allan said.

The study concluded Lake Superior is the healthiest of the Great Lakes.