This is a list of promotions that took place after the bombardment of Fort Sumter. Prior to that event, 79 Captains were in grade, of whom 13 'went South'. Farragut's date of rank as a Captain was 14 Sep 1855.
Those that either resigned their commissions, were dismissed from the service, or died between 14 Jan and 6 Jun 1861 are as follows:
Lawrence Rousseu, resigned 11 Feb 61
Isaac Mayo, dismissed 18 May 61
French Forrest, dismissed 19 Apr 61
Josiah Tattnall, resigned 21 Feb 61
Robert Bannatine Cunningham, died 13 Mar 61
Victor Moreaa Randolph, resigned 14 Jan 61
Franklin Buchanan, dismissed 22 Apr 61
George Nichols Hollins, dismissed 6 Jun 61
Duncan Nathaniel Ingraham, resigned 4 Feb 61
George Alexander Magruder, dismissed 22 Apr 61
Samuel Barron, dismissed 22 Apr 61
William Francis Lynch, resigned 21 Apr 61
Isaac Sears Sterrett, resigned 23 Apr 61
All of the above, except Mayo, Cunningham, and Magruder, became Captains in the Confederate Navy. Buchanan was promoted to Admiral on 21 Aug 1862.
I will list the 66 that remained loyal in another post.