0303.89.00.31 - Perch and pike perch (including yellow pike)

This HTS category encompasses frozen fish specifically identified as perch and pike perch, which includes the variety known as yellow pike. These are whole or headless, and gutted fish, not processed into fillets or other forms of fish meat that would fall under heading 0304. The classification is rooted in Chapter 3 of the Harmonized Tariff Schedule, which deals with fish and fish products.

To distinguish this category from its siblings, note that it specifically targets perch and pike perch species. For instance, it is differentiated from subheading 0303.89.00.28 which covers "Pike and pickerel," and from 0303.89.00.34 which pertains to "Sauger." Similarly, it is distinct from categories for whitefish and tilapias. The "Other" subcategory at this level, 0303.89.00.43, is reserved for fresh-water fish not otherwise specified within this particular group.

As this is a leaf node, there are no further subcategories under HTS code 0303.89.00.31. Therefore, the classification is definitive for frozen perch and pike perch. When classifying, key considerations include verifying the species against the defined scientific or common names and ensuring the product is presented in its frozen, whole, or gutted form, excluding any processed fish meat products.