Thunnus thynnus, commonly known as the Atlantic bluefin tuna, is a large, highly migratory pelagic fish in the family Scombridae. It is native to the North Atlantic Ocean, including the Mediterranean Sea and historically the Black Sea, with spawning grounds primarily in the Mediterranean and the Gulf of Mexico. The genus name Thunnus derives from the Greek thýnnos, meaning “tuna,” while the species epithet thynnus is a Latinized form of the same root, effectively meaning “tuna tuna.” The common name “Atlantic bluefin tuna” distinguishes it from related species such as Pacific bluefin (Thunnus orientalis) and southern bluefin (Thunnus maccoyii).

As an apex predator, the Atlantic bluefin tuna feeds on smaller fish, squid, and crustaceans and is capable of long transoceanic migrations. Atlantic bluefin tuna has been harvested since antiquity, with documented fisheries in the Mediterranean dating back to Phoenician and Roman times. In the modern era, it has become one of the most economically valuable and intensively managed fish species due to global demand for high-fat tuna in sushi and sashimi markets. As a food source, Thunnus thynnus is especially prized for its high intramuscular fat content and deep red flesh. In Mediterranean cuisines, it has historically been consumed fresh, salted, dried, or preserved in olive oil, and traditional tuna traps (tonnara in Italy, almadraba in Spain) were developed to harvest migrating fish. In Japanese cuisine, Atlantic bluefin is highly valued for sushi and sashimi, particularly for fatty belly cuts (toro). In Mediterranean traditions, specific cuts are air-dried or salt-cured, while in Japanese cuisine it is primarily consumed raw.

Thunnus thynnus contains omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), vitamin D (cholecalciferol), vitamin B12 (cobalamin), selenium, and taurine. Due to its long lifespan and high trophic level, Atlantic bluefin tuna can accumulate methylmercury, a neurotoxic organomercury compound formed in marine ecosystems, which is heat stable and not reduced by cooking. These nutritional and toxicological characteristics contribute to the species’ complex role in both gastronomy and public health discussions, especially in regions with high raw tuna consumption.