Date of Seniority Royal Navy 9 February 1815
James Alexander Mercer was appointed supernumerary to the HMS Tagus in 1810.
He was appointed Surgeon in the Royal Navy 9 February 1815.
James A. Mercer was employed as Surgeon Superintendent on three convict ship voyages to Australia:
to New South Wales in 1822.
to Van Diemen's Land in 1823.
to New South Wales in 1825
Qualifications and Awards
Treatise on the Accessary Organs of Hearing, comprisong the Special Pathology and Treatment of their Diseases, by James Mercer, M.D., written as a probationary essay for the Fellowship of the College of Surgeons in 1840 
Edinburgh, Scotland - University of Edinburgh...The following teachers being Fellows of the Royal College of Surgeons of Edinburgh
James Mercer for Practical Anatomy and Anatomical Demonstrations. 
 The Naval Chronicle
 Practical Observations on Aural Surgery: And the Nature and Treatment
by William Robert Wilde
 The London Medical Directory 1846 by John Churchill