170915-N-JO908-309 SAN DIEGO (Sept. 15, 2017) Vice Adm. John D. Alexander, commander, U.S. 3rd Fleet, gives remarks after assuming command from Vice Adm. Nora W. Tyson during a change of command and retirement ceremony held aboard the Nimitz-class aircraft carrier USS Theodore Roosevelt (CVN 71), Sept. 15. Alexander relieved Tyson, who is retiring after 38 years of honorable service. (U.S. Navy photo by Mass Communication Specialist 2nd Class Kory Alsberry/Released)