It could take months for maritime commerce in south Louisiana along the Mississippi River to return to pre-Hurricane Katrina levels, said the director of the Port of New Orleans. “In Plaquemines Parish, they can’t even tell where the ship channel was,” said Gary LaGrange, head of the New Orleans port. “The U.S. Army Corps of Engineers is so busy trying to repair the levees around New Orleans that they can’t release the personnel to go out to Southwest Pass and map the channel.” LaGrange, who was temporarily working out of the Port of West St. Mary Wednesday, said he...