Capt./Alt. stands for capitán de altura:

"Capt./Alt [Name] H"
http://www.umc.edu.ve/umcpro/sivrac/nuevapantalla/postgrado/...

"[Same name]
Profesor Asociado, Capitán de Altura"
https://www.linkedin.com/vsearch/p?orig=TSEO_SN&firstName=Al...

"Capitán de altura" is a merchant navy term. We've had it before, and the accepted answer was "sea captain":
http://www.proz.com/kudoz/spanish_to_english/ships_sailing_m...

But I think the better term is "Master Mariner". A sea captain is basically any master of a vessel. But a "capitán de altura" is a authorised as a master of an ocean-going vessel (which is what "altura" refers to), and indeed it seems to be a title denoted that the person can captain any vessel. This is from Mexico, but I think the meaning of the term is the same:

"El curso de Actualización para Capitán de Altura, otorga a los participantes los elementos necesarios para que desarrollen las habilidades que garanticen la operación con el máximo de seguridad de cualquier buque mercante, plataforma y demás artefactos que requieran de tripulación de acuerdo a la Legislación Nacional y al Convenio Internacional sobre Normas de Formación, Titulación y Guardia para la Gente de Mar (STCW´95)."
http://www.fidena.gob.mx/index.php/educacion-continua/cursos...

Well, a master mariner is that: someone with an "unlimited" licence:
http://en.wikipedia.org/wiki/Master_mariner
See also
http://en.wikipedia.org/wiki/Sea_captain

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Note added at 1 hr (2014-04-10 20:45:59 GMT)
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Here's the man himself; I'll hide the name, just as you did:

"rector de la Universidad Nacional Experimental Marítima del Caribe (UMC), Capitán de Altura J..... C........ G......... S............"
http://www.umc.edu.ve/umcpro/index.php/inicio/192-rector-de-...