The salary of a member of Council shall be three hundred dollars ($300.00) per year for the first term beginning January 1, 1972. For the terms thereafter the Council may determine and fix the salary of its members, but the salary of a member of Council shall not be increased or decreased during the elective term of office which he is serving at the time of the increase or decrease. If the Council determines to change the established salary of members in respect to a succeeding term of office such change must be made by the Council before the first day of January next preceding the regular Municipal election. Unless and until the salary is so changed, it shall remain as last fixed.