This industry comprises establishments primarily engaged in the merchant wholesale distribution of fish and seafood (except canned or packaged frozen). Cross-References. Establishments primarily engaged in-- ? Merchant wholesale distribution of packaged frozen fish and seafood--are classified in Industry 424420, Packaged Frozen Food Merchant Wholesalers; ? Merchant wholesale distribution of canned fish and seafood--are classified in Industry 424490, Other Grocery and Related Products Merchant Wholesalers; and ? Canning, smoking, salting, drying, or freezing seafood and shucking and packing fresh shellfish--are classified in Industry 31171, Seafood Product Preparation and Packaging.