The traditional definition of caviar is not simply "fish eggs." True caviar comes solely from fish of the Acipenseridae family, also known as sturgeon. The eggs are harvested from the female sturgeon before fertilization and then cured with salt to enhance the flavor and increase the shelf-life of the finished product. This combination of unfertilized sturgeon eggs and salt is the delicacy known as caviar.
In many countries it is considered unlawful to label any fish roe not from a sturgeon as caviar. Here in the U.S.A. however, it is common practice to label roes from salmon, trout, paddlefish, bowfin and other non-sturgeon species as "caviar", even though they are not caviar by definition.
Definition of caviar: "salted, unfertilized fish eggs from the sturgeon family (acipenseridae)"
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