The district shall be governed by a board of port commissioners. The board consists of five members. Two of the commissioners shall be appointed by the board of supervisors of the county in which the district is located. Two of the commissioners shall be appointed by the city council of the municipal corporation situated in the district. The board of supervisors, together with five members of the city council, appointed by the mayor of the municipality in the district constitute a board of election to appoint the other commissioner. This commissioner shall be chairman of the board. A majority vote is necessary for the appointment of the chairman of the board. An auditor shall be appointed by the board of port commissioners and approved by the board of supervisors and the city council.