All of the members of the Board shall be bona fide citizens and residents of the City and shall be over the age of eighteen (18). The position of a Commissioner shall be vacant if that Commissioner moves permanently from the City or submits a resignation. Vacancies in the Board shall be filled by appointment of the Mayor, with approval of the Council. The appointed Commissioner shall fill the term for the unexpired term or until the next general municipal election is held, whichever occurs first.