This might help in your search of a list of Port Hudson Prisoners.

My great grandfather, James Holliman was required to sign an oath, on July 11, 1863, that he does hereby give his parole of honor not to bear arms against the United States..........until regularly exchanged. Signed by T.E. Chickersing, Colonel 3d Reg't Mass. Cavalry, Provost Marshal and Paroling Officer