The council may also appoint a harbormaster, wharfmaster, port wardens, and such other officers as may be necessary for the enforcement of all such ordinances and regulations as the council may lawfully enact and prescribe, in respect to and over the navigable waters, harbors, wharves, docks, landings and basins, within the city, and in respect to the navigation, trade, and commerce of the city and prescribe the powers and duties of such harbormaster and other officers, and to fix the compensation to be paid them.