Spanish term (edited): alcalde de mar

See my explanation in the discussion section. I'm not very confident of this answer, but I think it's the idea. I think it is more than 'port captain', 'harbor master', etc. (My dad was briefly a port captain after a long career as a sea captain.) Here are some examples:

Port operators and maritime administrators face increased demands for efficient operations, management, security, and environmental management. ...
www.esri.com/industries/ports-maritime/index.html

A workshop for Regional Senior Maritime Administrators was held in Jamaica ... It was attended by the senior maritime administrators representing the ...
www.sjofartsverket.se/pages/19657/59-4-1.pdf

This conference will discuss topics of interest to shipping company executives, maritime administrators, seafarers, port authorities and port facility ...
www.nm-uni.eu/events

Global Maritime Academy - About GMA
We are committed to producing high quality personnel and maritime administrators that are capable of meeting the challenges, demands and changes in the ...
gmaan.com/aboutgma.html

Lectures on maritime society from domestic and overseas guest speakers who are maritime administrators and reserchers. Elementary, secondary, and high ...
www.iamu-edu.org/members/kufms.php

... ship managers and officers, marine surveyors, maritime administrators, government representatives, trade union officials and maritime educators. ...
www.gre.ac.uk › Schools › Greenwich Maritime Institute