Petty Officer 3rd Class Kent-Erik Hedberg, Marine Safety Detachment Massena worked with a crewmember to get a sample of ballast water from the motor vessel Eider, in Montreal, June 3, 2008. The U.S. Coast Guard inspects all vessels' ballast water before they enter the Great Lakes to prevent invasive species inhabiting ecosystems. Photo by Petty Officer 3rd Class William B. Mitchell.