In addition to any other licenses and charges imposed by law, there shall be collected by the director of the department of agriculture and paid to the director of the department of revenue for deposit in the aquaculture marketing development fund an additional charge of three dollars per ton of fish food or fraction thereof purchased by commercial producers in this state. As used in sections 275.450 to 275.455, the term “fish food”, means food, purchased in bulk or bag quantities, used to feed fish, whether or not such food is used for fish held for sale, and the term “commercial producer” means a commercial producer or seller of fish or fish products who purchases at least two thousand pounds of fish food in a calendar year, but such term shall not include the state, any state department or any political subdivision of the state. The charges shall be paid and collected pursuant to section 275.455.