Preserving and processing fish and other marine foods. These processes include such operations as salting, drying, dehydrating, smoking, curing, pickling, packing in air-tight containers, and quick-freezing. Icing, salting, filleting of fish catch are classified in groups 041 (Ocean and coastal water fishing, except factory-vessel fishing) or 043 (Inland water fishing), whichever is appropriate; and processing of the catch aboard fishing vessels is classified in group 042 (Factory vessel fishing).