NEW ORLEANS — A group of 30 endangered sea turtles are being treated for hypothermia and pneumonia in Louisiana after a sudden cold spell nearly froze them in New England waters, caretakers say. The Audubon Nature Institute’s Coastal Wildlife Network announced this week that it took in the reptiles at a New Orleans rehabilitation facility after they were brought on a rough ride from Massachusetts. The rare Kemp’s ridley sea turtles, considered among the world’s most endangered sea turtles, were swimming off the Massachusetts coast before Thanksgiving when the cold snap and high winds sickened hundreds of them in what experts called a “massive cold-stunning event,” according to the organization. Nearly killed by falling ocean temperatures, many of the turtles have since been moved to wildlife centers along the Atlantic and Gulf coasts. “When these cold snaps happen, the turtles can go into shock,” The Times-Picayune/The New Orleans Advocate quoted Gabriella Harlamert, a rehabilitation coordinator, as saying.