What fish is the primary source of caviar?

The primary source of caviar is sturgeon, which refers to the roe (fish eggs) harvested from these fish. Sturgeon is a unique fish genus known for producing high-quality caviar, particularly prized varieties such as Beluga, Osetra, and Sevruga. The specific qualities of sturgeon caviar, including taste, texture, and size of the eggs, are considered superior to caviar from other fish species.

In contrast, while salmon, tuna, and trout may also produce roe, their eggs are not classified as caviar in the traditional sense. Salmon roe is often used in various culinary applications, especially in sushi, but it does not have the same esteemed status as sturgeon caviar. Thus, sturgeon is the definitive source of true caviar, which is why it is the correct response in this context.