Although all fish eggs are theoretical “roe,” not all “roe” is caviar. The name caviar only refers to the roe of sturgeons of the Acipenseridae family. Salmon roe, as well as roe from whitefish, trout, cod, red caviar, ikura, and tobiko, are “caviar alternatives” rather than caviar.
No, albeit many other fish roes (such as salmon caviar) utilize the name for marketing purposes to improve perception and acceptance of their product.
For nearly a thousand years, and maybe over two thousand years, the Persians have consumed xâvyâr (caviar). Descriptions of it on the tables of Byzantine aristocrats in the 10th century were the earliest recordings in the West. Because xâvyâr means egg-bearing, some have speculated that it might refer to any giant fish’s egg. What we do know is that the only xâvyâr served to aristocracy and documented by the Byzantinse were sturgeon fish eggs.
Avyron is the Greek word for egg, while havyar is the Turkish word for caviar. Thus, the term caviar began as xâvyâr and traveled via Turkey, Greece, Italy (caviale), and France (caviar) before arriving in the British Isles and becoming part of the English language. Caviar was entrenched as a Russian meal and specifically a Royal Russian food with the establishment of Russia and, in particular, Russian involvement with the West during and after Peter the Great. Aside: caviar is known in Russia as ikra (икрa), which means “completely unlike caviar.”
Today, caviar is a term that solely refers to sturgeon eggs (for example in the USA this is mandated by the FDA). However, you should be aware of the following:
There are several different varieties of sturgeon, and each has its own name for its eggs; and
It is permitted to use qualifier names that clearly separate it from sturgeon eggs. As a result, both salmon and lump fish caviar are acceptable.