Annually at the regular meetings of the city council or commission in April the council or commission shall elect a member or members of the board of education to succeed those whose term or terms of office expire that year. Members of the city board of education shall assume office at the next regular meeting of the city board of education in June following their appointment. The terms of office of members of the city board of education shall be five years, and the term of one member shall expire annually. A member shall serve on the board until his or her successor assumes office. In the event of a vacancy in the membership of the city board of education by resignation or otherwise, the fact shall be reported to the city council or commission by the board, and the council or commission shall elect a person to fill the vacancy for the unexpired term.