Traditionally, the term "caviar" refers to the salt-cured roe (eggs) of the sturgeon fish.
Sturgeon is a large, prehistoric-looking fish that is found in many parts of the world, including the Caspian Sea, the Black Sea, and the rivers of North America. The eggs of sturgeon have been prized as a delicacy for centuries and are traditionally cured with salt to make caviar. The most highly prized caviar comes from sturgeon species such as Beluga, Osetra, and Sevruga, which are found in the Caspian and Black Sea regions. However, overfishing and habitat destruction have led to a decline in sturgeon populations in many parts of the world, and many species are now endangered. As a result, caviar is now often produced from other fish, such as salmon and trout, and is sometimes referred to as "imitation caviar".