For the purpose of meeting the expense attendant upon the general and special supervision of the harbor and Port of Mobile and the performance of the duties and service required by this chapter, and by the rules and regulations herein authorized, and of similar duties relating to the supervision of the harbor and port required by other statutory provisions, the fees and charges, general and special, as may be fixed and determined by the Alabama State Port Authority, are hereby imposed against all owners, charterers, or persons in possession, to be collected by the port authority on vessels using the harbor as defined in this chapter. The port authority is authorized and empowered to collect such fees and charges by any appropriate proceedings in personam or in rem, when authorized by the Director or the Board of Directors of the Alabama State Port Authority. The Alabama State Port Authority is authorized to make such reasonable changes in such charges, or any of them, by raising or lowering them as may be necessary to carry out the purpose of this chapter, and to lower the same as may be necessary to protect the port from discrimination at other ports.