Except in the case of a service area board, each member of a committee, board or commission shall be appointed by the mayor subject to approval of the assembly. The terms of initial appointment to a committee, board or commission shall be staggered so that, as nearly as possible, a pro rata number of members shall be appointed for each year during the regular term of office established for the members of the committee, board or commission. A member shall serve until the expiration of the member’s term. The regular term of a member of a committee, board or commission shall commence on December 1st of the year of appointment and shall expire on November 30th of the year the member’s term expires or until filled by the member’s successor. In the case of a service area board, the assembly may provide for appointed or elected boards to supervise the furnishing of services within a service area.