Mich. Comp. Laws § 120.10
A member of the commission shall continue to serve until a successor is appointed and qualified. A majority of the port commissioners constitutes a quorum for the transaction of business and the concurrence of the majority of the commissioners shall be necessary for the passage of a resolution. The business of the commission shall not be transacted unless there are in office at least a majority of the full number of commissioners fixed by law. A person shall not be eligible to hold the office of port commissioner unless the person is a qualified voter, a property owner within the port district, and is and has been a resident in the port district for at least 3 years. A member of a port commission shall not have a financial interest in the profits of a contract or business transaction with the port district. This prohibition shall not apply if the commission declares, on the record, and it is found by unanimous vote of the members present not having a financial interest, that the best interests of the district are to be served by the waiving of the prohibition in a particular case, and then only if competitive purchasing and contracting are used in the case, or if the members of the commission not having an interest, unanimously determine that competitive purchasing or contracting is not feasible in that particular case. A vacancy in the office of port commissioner may occur by death, resignation, or removal as provided in this section, by conviction of a felony, by statutory disqualification, or by a permanent disability preventing the proper discharge of the duties of a commissioner. The county board of commissioners may remove a port commissioner for habitual misconduct, misfeasance, habitual or wilful neglect of duty, or when the board is satisfied that the officer is incompetent to properly execute the duties of the office. A member of a port district appointed by the governing body of a city or township or cities or townships as provided in section 9, may be removed by the governing body for any of the reasons set forth in this section. A commissioner, within 20 days after the commission receives notice of appointment, shall qualify by taking and subscribing the constitutional oath of office.
MCL 120.10