March 30 (Reuters) - A Florida aquarium has reached a deal with animal welfare advocates to release Lolita, a 5,000-pound (2,268 kg) killer whale held in captivity for more than half a century, officials said on Thursday. The process to return Lolita to her "home waters" was years in the making, beginning with the transfer of the aquarium's ownership to The Dolphin Co, Miami-Dade County Mayor Daniella Levine Cava said at a news conference. See here for a complete list of exchanges and delays