A man living in Mexico says he was able to survive 13 months at sea by eating fish, birds and turtles.  Jose Alvarenga says he and a teen boy set out for a day of shark fishing on December 21, 2012, but a storm blew them off course.  The 37-year-old man says after about a month, the teen died.  Last week Alvarenga washed ashore on the remote Marshall Islands some 5,500 miles away.  Officials are reacting cautiously to the man's story, but they say that if true, it would rank among the greatest tales ever of survival at sea.