0303.45.01 - Atlantic and Pacific bluefin tunas (Thunnus thynnus, Thunnus orientalis)

This HTS category, 0303.45.01, specifically classifies frozen Atlantic and Pacific bluefin tunas, belonging to the species *Thunnus thynnus* and *Thunnus orientalis* respectively. These tunas are distinguished by their size, coloration, and migratory patterns, which differentiate them from other tuna species within heading 0303.

Unlike its sibling categories which cover other specific tuna types such as Albacore (*Thunnus alalunga*), Yellowfin (*Thunnus albacares*), Skipjack (*Katsuwonus pelamis*), Bigeye (*Thunnus obesus*), and Southern Bluefin (*Thunnus maccoyii*), this subheading focuses exclusively on the bluefin varieties. The distinction is crucial for trade statistics and potential regulatory measures related to specific fish populations.

This classification is further subdivided to delineate between the two primary species of bluefin tuna covered. Subcategory 0303.45.01.10 pertains to frozen Atlantic bluefin tuna (*Thunnus thynnus*), while 0303.45.01.50 covers frozen Pacific bluefin tuna (*Thunnus orientalis*). This granular breakdown allows for more precise tracking and management of these distinct, high-value tuna populations.