Thunnus obesus, commonly known as the bigeye tuna, is a species of tuna found in tropical and subtropical oceans worldwide. It is characterized by its large eyes, streamlined body, and dark blue dorsal side, which helps it blend into the ocean depths. Bigeye tuna can grow up to 2 meters in length and weigh over 180 kilograms. This species is highly valued in commercial fishing, particularly in the sushi and sashimi markets. Thunnus obesus is known for its rich flavor and firm texture, making it a popular choice among seafood lovers. However, overfishing has raised concerns about its population sustainability.