The St. Marys River has reopened to vessel traffic after a U.S.-flagged Great Lakes freighter struck a channel light in the waterway.At approximately 1 a.m. on Thursday, the 730-foot bulk carrier American Mariner suffered a marine casualty and went bow-first into the Munuscong Junction Light, the U.S. Coast Guard said. The incident occurred in Munuscong Lake, which is a section of the St.