A person is not liable for the fisheries business tax under AS 43.75.015 when the fishery resource is processed aboard a fishing vessel if (1) the vessel is operated as a commercial fishing vessel under a valid commercial fishing license;
(2) the fishery resource is not processed beyond heading, gutting or cleaning, freezing, and glazing;
(3) the fishery resource was caught by the vessel; and
(4) the fishery resource is sold to a fisheries business licensed under this chapter.