U.S. Navy-trained dolphins and their handlers will participate in a last-ditch effort to catch, enclose and protect the last few dozen of Mexico's critically endangered vaquita porpoises to save them from extinction. International experts confirmed the participation of the Navy Marine Mammal Program in the effort, which is expected to start sometime this spring. Jim Fallin of the U.S. Navy Space and Naval Warfare Systems Center Pacific said Tuesd…