A 65-mile stretch of the Mississippi River, including the Port of New Orleans, was closed to all water traffic Sunday as crews cleaned up oil that spilled from a barge after it ran into a towboat between Baton Rouge and New Orleans, the Coast Guard said. Officials don’t know how much oil spilled, but only a sheen was reported on the river following the collision, which happened Saturday afternoon near Vacherie, 47 miles west of New Orleans by land, said Coast Guard Petty Officer Bill Colclough.