There is levied upon each licensed bar pilot engaged in service as a bar pilot under this chapter a license or privilege tax in the sum of one hundred dollars ($100) annually plus any reasonable additional assessment that arises and is necessarily incurred out of the performance by the State Pilotage Commission of its duties imposed by law, to be paid to the secretary of the commission and to be used for defraying all expenses and expenditures of the commission accruing under this chapter. The commission, by proper resolutions, may permit the tax to be paid quarterly. The privilege or license taxes paid to the secretary of the commission shall become a part of the funds of the commission and shall be deposited by the secretary and otherwise handled and disbursed, as required by this chapter.